Zizyphus Jujube Fruits is one of the oldest medicinal plants which can heal wounds through its antimicrobial and anti-inflammatory properties. This study aimed to determine the effect of jujube lotion on the recovery of breast fissure. This double-blind clinical trial recruited 100 primiparous lactating women who were randomly divided into two groups. In Jujube group, mothers used 0.5 mL of Fruit Lotion, and in control group mothers applied 4-5 drops of their breast milk five times a day, after breastfeeding. Both groups were examined on the 7th and 14th days after childbirth. The damage severity was assessed using the Amir scale and the presence or absence of nipple discharge was recorded. A significant difference was observed between the two groups in the extent of nipple damage before intervention on the 3rd day after childbirth and after intervention on the 7th and 14th days after childbirth (P = 0/02، P = 0/000). No significant difference was observed in sore nipple discharge between the two groups before the study and on the 7th day, while a statistically significant difference was observed between the two groups on the 14th day . The finding of this study revealed that the Zizyphus jujube fruits lotion heals nipple fissure faster and better than breast milk.Nipple fissure is a common problem during breastfeeding.  Breast milk is the gold standard and the safest way to feed infants in the world , 2. AfteIn general, flavonoid and phenolic compounds that herbal extracts produce help neutralize free radicals or exert their biological effects, so they are usually used for the treatment of topical wounds , 13. Zizyphus jujube Fruit is one of the species used for the treatment of wounds and burns. The Zizyphus jujube Fruit has been described as the fruit of life. Ancient Chinese discovered the unique and medicinal properties of this fruit thousands of years ago  have studied the healing effect of Zizyphus jujube lotion on burn injuries of mice and showed that the Zizyphus jujube lotion is effective for healing those wounds  studied Analgesic, anti-stress, and sedation effects of Zizyphus jujube juice in an experimental environment on mice and the results indicated that Zizyphus jujube juice has analgesic, anti-stress, and sedation effects and the researcher believed that these effects happen due to decrease in the activities of monoamines  after being approved by the ethics committee. This study recruited primiparous women presenting to the Obstetrics and Gynecology Clinic of Ghaem Hospital affiliated to Kerman University of Medical Sciences on the third day after childbirth for screening their newborns for hypothyroidism (a routine screening in Iran) from October 2015 to March 2016 and they were examined in terms of breast fissure.Written informed consent was first obtained from mothers after explaining the purpose of the study and the methodology. Zizyphus jujube lotion by using excels software. In this study, after consulting with a professor in field of statistics, the numbers of samples were achieved by the following relation: The samples which had entrance criterion features were selected and then they were randomly placed in two groups of breast milk and The least required number of samples in the following relation is 50 persons.α=0.05          →𝛽 = 0. 2 →1 is the percentage of recovery in Zizyphus jujube lotion group and P2 is the percentage of recovery in breast milk group , baby’s birth weight between 2500 and 4000 gr., baby’s not having frenulum breve, baby’s not having minor anomalies of the mouth, palate, jaw, and face, lack of allergy to topical medications, exclusive breastfeeding, non-use of an artificial nipple and breast pump, mothers’ not having diabetes or any other internal diseases and mental disorders.Zizyphus Jujube Fruits lotion, using medications for sore nipples or analgesics during the study, using suggested treatments fewer than four times, having puerperal fever, mastitis, and baby’s developing oral infections and diseases. In this study, the data were collected through demographics and obstetrics questionnaire, health assessment form, visual analogue scale, Amir Scale, nipple discharge scale, and inventory of Zizyphus jujube Fruit lotion side effects. Content validity was used to determine the validity of the demographics and obstetrics questionnaire, health assessment form, and inventory of Zizyphus jujube Fruit lotion side effects . To determine the reliability of the health assessment form, the test re-test was used on the third and 14th days and its reliability coefficient was obtained 0.95. The Amir scale was used to evaluate nipple fissure. In this scale, zero means no damage, 1-2 mm mild damage, 3-9 mm moderate damage, and 10 mm or higher severe damage. This scale is a valid instrument, whose reliability and validity have been confirmed in the previous studies  they divide randomly into two 50-person groups of breast milk and Zizyphus jujube lotion was made as following: first, 700 grams of fresh Zizyphus jujube fruit was bought from the traditional bazar of Kerman, the pits were removed after it was dried, and the rest of it was powdered. 210 mg of the juice of Zizyphus jujube fruit with 54% efficiency was made by using 96%-ethanol by pharmacy department of Shahid Beheshti University. At the day of referral, before treatment, correct techniques of breastfeeding were instructed face to face and the benefits of breastfeeding were explained to mothers for mothers’ and babies’ health (in order to encourage mothers to continue breastfeeding and their treatment). Mothers feed their infants in front of the researcher and correct method of breastfeeding was evaluated and Amir Scale was completed.Zizyphus jujube fruit lotion, the following method was applied:Considering the similar studies, in order to coordinate the receiving amount and usage times of breast milk and Zizyphus Jujube Fruit lotion group were advised to apply 0.5 mL of Zizyphus jujube Fruit lotion on the nipple and areola 5 times a day after each breastfeeding, and women in the breast milk group were advised to apply 4-5 drops of their own milk on the nipple and areola 5 times a day after each nursing. The women in both groups were asked to go to the relevant hospital on the 7th and 14th days after childbirth to assess extent of damage and presence or absence of discharge from sore nipples  was used.Given that the response variable was ordinal and the data were not normally distributed, extent of damage were first compared to three days using Friedman test and then, the responses were compared between the two groups using the Mann-Whitney test. Furthermore, in cases in which Mann-Whitney test was statistically significant, therapeutic cycles were compared mutually using the Wilcoxon test. To examine the presence or absence of discharge from sore nipples, a comparison was made using the Cochran test in three days and responses were then compared between the two groups using the chi-square test.Zizyphus jujube lotion was reported on the side of mother.The two groups did not have any sample fall and also no side effect of using Zizyphus jujube Fruit lotion and breast milk. Obstetrics and demographics characteristics are presented in (This study recruited 100 primiparous lactating women with sore nipples who were divided into two groups of 50 receiving ented in . Both grp = 0.8). There was a statistically significant difference in lesion severity score on the third day after childbirth (before intervention) and the 7th day after childbirth (after intervention), as well as on the third and 14th days after childbirth between the two groups . In this study, jujube ointments 1% and 10% were used to evaluate burn wound healing, which revealed that jujube ointment 1% was more effective than jujube ointment 10%. Therefore, by increasing concentrations of jujube extract, the wound healing effect reduced. This study suggested that the healing effect of jujube is due to its large amounts of unsaturated fatty acids, flavonoids, and tryptonoids. Fatty acids increase collagen synthesis and ascorbic acid, through decreasing macrophages, increasing fibroblasts, stimulating angiogenesis, and anti-inflammatory effects improving healing wounds . At doses of 400 and 200 mg/Kg, jujube extracts reduced inflammation 47.4% and 35.5%, respectively. In this study, alkaloids, flavonoids, glycosides, and terpenoids were found in the jujube juice. Flavonoids and terpenoids have anti-inflammatory and anti-allergic properties by reducing the expression of nitric oxide, prostaglandins, and reducing histamine release  increases. 200 and 400 mg/Kg of jujube extracts can reduce acute and chronic inflammation caused by carrageenan by reducing the expression of nitric oxide and prostaglandins . The wound healing potential of jujube peel extract has been attributed to its tannin and flavonoid compounds which cause wound contraction and increase protein content and epithelialization of the wound  of jujube peel extract and 100 (mg/Kg) of diclofenac sodium had inhibitory effects on inflammation. This inhibitory effect at a dose of 600 mg of jujube peel extract was higher than other doses, but less than the diclofenac sodium group (A study conducted on the effect of jujube peel ointment on wounds in mice found that wounds healed more quickly in the group receiving he wound . Thus, tum group .Zizyphus jujube, we can explain anti-inflammatory effects of this fruit. In the study done on the extract of Zizyphus jujube leaf in reducing inflammation, it was seen that the leaf of Zizyphus jujube has compounds such as phenols, terpenoids and epi catechin, which avoid the spread of inflammatory mediators (Zizyphus jujube and anti-inflammatory effects of Zizyphus jujube can be explained through this study.Due to the large amounts of polyphenol, steroid, vitamin C and A in the skin of ediators . On the ediators . The resIn other similar studies, olive oil and green tea with compounds similar to jujube fruit were effective for the recovery of breast fissure , 33.Zizyphus Jujube Fruit lotion was effective in reducing nipple pain due to having compounds, such as cyclopeptides, catechins, and phenolic acids (In our study, the ic acids , 35. Accic acids  and 40. The results showed that Zizyphus Jujube Fruit lotion can treat sore nipples faster than breast milk over a period of 10 days. Also, nipple pain in the jujube lotion group was less than the breast milk group. Given the effect of jujube lotion on the recovery of breast fissure and lack of adverse side effects in this study, it seems that the Zizyphu Jujube Fruits lotion can be used for the treatment of breast fissure.


Electrically conductive nanofiber is well known as an excellent nanostructured material for its outstanding performances. In this work, poly (PEDOT)-coated polyvinyl alcohol-graphene oxide (PVA-GO)-conducting nanofibers were fabricated via a combined method using electrospinning and electropolymerization techniques. During electrospinning, the concentration of PVA-GO solution and the applied voltage were deliberately altered in order to determine the optimized electrospinning conditions. The optimized parameters obtained were 0.1 mg/mL of GO concentration with electrospinning voltage of 15 kV, which displayed smooth nanofibrous morphology and smaller diameter distribution. The electrospun PVA-GO nanofiber mats were further modified by coating with the conjugated polymer, PEDOT, using electropolymerization technique which is a facile approach for coating the nanofibers. SEM images of the obtained nanofibers indicated that cauliflower-like structures of PEDOT were successfully grown on the surface of the electrospun nanofibers during the potentiostatic mode of the electropolymerization process. The conductive nature of PEDOT coating strongly depends on the different electropolymerization parameters, resulting in good conductivity of PEDOT-coated nanofibers. The optimum electropolymerization of PEDOT was at a potential of 1.2 V in 5 min. The electrochemical measurements demonstrated that the fabricated PVA–GO/PEDOT composite nanofiber could enhance the current response and reduce the charge transfer resistance of the nanofiber. Recently, nanofibers have been broadly investigated as high-performance materials due to their unique and remarkable properties which exhibit tremendous advantages. Nanofibers have attracted a great deal of attention because of their excellent characteristics including a high surface area to volume ratio, low specific mass, and extensive porosity  which maPreviously, various techniques have been employed to obtain suitable polymer nanofibers for different purposes such as electrospinning, template synthesis, drawing, phase separation, and self-assembly . At presPoly (PEDOT) as one of the conductive polymers from polythiophene derivatives has been widely explored due to its excellent environmental and thermal stability, high-speed electron transfer, good mechanical strength, and relatively high optical transparency when in its electrically conductive state . HoweverAnother important approach in producing polymer-based composites is the incorporation of carbon-based materials such as carbon nanotubes (CNT) and graphene derivatives into the nanofibers. The complete dispersion of nanofiller represents another challenge that can be countered by specific material, in order to increase their affinity for the polymer matrix in an appropriate solvent. This issue can be overcome by selecting a kind of effective nanofiller to be encapsulated into an electrospun nanofiber matrix. In this study, graphene oxide (GO) is appointed as the best candidate for nanofillers to be reinforced with a hydrophilic polymer such as polyvinyl alcohol (PVA) due to its abundance of hydrophilic groups on its surface. Additionally, PVA is considered as a commonly used electrospinnable polymer due to its processibility, good biodegradability, non-toxicity, and good mechanical properties . TherefoIn this study, conductive nanofibers were fabricated by a dual process using electrospinning and electropolymerization techniques. An attempt has been made to optimize the conditions for electrospinning and electropolymerization to obtain uniform and continuous nanoscale fibers with good electrical conductivity. During the electrospinning, optimization of some parameters was carried out to obtain the smallest diameter of PVA and PVA-GO nanofibrous structures. Finally, the effect of the electropolymerization potential and time of PEDOT onto the electrospun nanofibers was studied by electrochemical measurements.4, 95.0%) were purchased from Sigma Aldrich. Acetonitrile  was obtained from J.T.Baker. Potassium ferricyanide (K3[Fe(CN)6]), potassium ferrocyanide (K4[Fe(CN)6]), and KCl were obtained from BDH Analar. All reagents in this experiment were in analytical grade and used as received without further purification. The indium tin oxide (ITO) glass substrate was purchased from Xin Yan Technology Ltd. The ITO glass substrate was cleaned by sonication in acetone, ethanol, and deionized water (DI) sequentially for 15 min each. DI water (resistivity ~18.2 MΩ) was used throughout the experiments.Polyvinyl alcohol (PVA) , 3,4-ethylenedioxythiophene , lithium perchlorate  3− as a redox probe containing 0.1 M KCl as supporting electrolyte. The CV potential range was scanned from −0.2 to 0.6 V with varied scan rate from 2 to 100 mV/s at room temperature. Electrochemical impedance spectroscopy (EIS) was used to study the electrochemical and surface reactions of electrodes. This technique gives information about the interfacial properties of PEDOT-coated nanofibers. The measurements were carried out to in solution consists of equimolar 5 mM [Fe(CN)6]3−/4− redox system containing 0.1 M KCl using a frequency range between 0.01 and 10 kHz at open circuit potential (OCP), by using a sinusoidal excitation signal (single sine) with an excitation amplitude of 10 mV.The morphology of the nanofibers on the surface of indium tin oxide-coated glass was examined by JOEL JSM-6400 scanning electron microscope (SEM). The samples were mounted on aluminum stubs using double-sided carbon-coated tape and were vacuumed and gold coated for 10 min prior to analysis by using sputter coater. The analysis was carried out at accelerating voltage of 10–15 k. A computer-controlled potentiostat/galvanostat  was used for cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The measurements were carried out in a standard three-electrode setup with a platinum coil as the counter electrode and Ag/AgCl used as the reference electrode. The obtained nanofiber on the ITO glass was used as the working electrode. In this study, CV measurements were performed in 10 mM [Fe(CN)Four different voltages were applied  to prepare PVA nanofibers while the other parameters were kept constant and the SEM micrographs are displayed in Fig. However, increasing the spinning voltage would contribute to the accumulation of charged and draw more solution out of the capillary tip which resulted in the difficulty of jet elongation . This efThe optimized parameters to produce PVA nanofibers were used to fabricate PVA-GO nanofibers. GO acts as a nanofiller to enhance the properties of the electrospun nanofibers. As suggested by Jiang et al. , the incAs can be clearly seen in Fig. The coating of nanofibers with PEDOT could be an efficient alternative to produce highly conductive nanofibers with good electrochemical performances. For coating purposes, an effective technique namely chronoamperometric was introduced, which can produce PEDOT polymer layer on PVA and PVA-GO nanofibers with high conductivity values. Therefore, the cyclic voltammetry measurement was performed to determine the onset oxidation potential and the suitable potential range for the electropolymerization of PEDOT on the electrospun nanofibers. The electropolymerization potential is important in the preparation of the polymer as it could affect the growth of the polymer process and might cause some changes in the structure of the polymer film. Therefore, it is crucial to choose the appropriately applied potential for the electropolymerization process.4 as supporting electrolyte in acetonitrile. The onset potential was determined from the intersection of the tangents drawn at the baseline current and the oxidation current slope in the CV [Figure n the CV . It was •+, occurs which initiates the polymerization process. The initiation step involves the anodic oxidation of EDOT monomers to radical cations which then dimerize and deprotonate. After the deprotonating step, the dimer is reoxidized and the process continues with the formation of oligomer radical cation species, which interact with other EDOT•+, forming the PEDOT polymer. The electrochemical polymerization of EDOT is described by Diaz’s mechanism [A crossover was observed between the forward scan and reverse scan in the CV, called as “nucleation loop.” This phenomenon is attributed to the initial stage of nucleation process for conductive polymer film which corresponds to the theory of metal deposition . The oxiechanism . Moreoveechanism .Figure The deposition of PEDOT on PVA-GO nanofibers displays significant changes in the PEDOT morphologies. The surface of the PVA-GO/PEDOT1.0V nanofibers Fig. d displayDifferent electropolymerization time of PEDOT was employed to control the thickness and surface morphologies of nanofibers. The electropolymerization time was varied from 1 to 15 min to obtain a homogenous and highly conductive coating of PEDOT on the electrospun nanofibers. Figure However, as the deposition time is extended to 5 min, there is a formation of the cauliflower-like structure of PEDOT nanoparticles Fig. b. It wasA similar pattern was observed for PEDOT electrodeposited on the surface of PVA-GO nanofibers. As depicted in SEM images, the diameter of PVA-GO/PEDOT10m Fig. e nanofib3Fe(CN)6 containing 0.1 M KCl solution. The values of the peak current for the prepared nanofibers were measured by extrapolating the preceding baseline current.In order to understand the electrochemical behavior of PEDOT deposited on nanofibers at different electropolymerization potentials, cyclic voltammetry measurements were swept between −0.2 and 0.6 V in 1.0 mM KAs can be seen in Fig. It was observed that when the electropolymerization potential of PEDOT on bare ITO is increased from 1.0 to 1.2 V, the peak current increases Fig. c. A simiA drastic drop in the peak current is noticed as the electropolymerization potential is further increased to 1.5 V. This might be due to the structure of PEDOT becomes denser and the fibrous structures of the coated nanofibers become less pronounce as observed in the SEM images. Additionally, similar behavior has been reported that PEDOT electrodeposited at high potential (over 1.4 V) may undergo overoxidation which leads to degradation of PEDOT and decreases the conductivity of polymer film . TherefoIn contrast, the nanofibrous structure of PVA-GO/PEDOT1.2V is seen clearly which certainly increases the active surface area of the nanofibers. The CV revealed that both anodic and cathodic peak currents are clearly defined compared to PVA-GO/PEDOT1.5V nanofibers Fig. b. This pIn order to study the effect of electropolymerization time, PEDOT was electropolymerized at a constant potential (1.2 V) and varying the electropolymerization time from 1 to 15 min. By varying the deposition time, the physical properties such as the particles size, surface roughness, and thickness of PEDOT layer can be controlled to obtain a better electrochemical performance of coated nanofibers. The movement of ions to the electrode is expected to be easier if the thickness of the PEDOT layer is optimized which provides a high amount of active site area. As presented in Fig. For PVA-GO/PEDOT1m nanofibers, the peak current is 378.75 mA. Subsequently, the value is further increased when the electropolymerization time increases to 5 min (550.59 mA). At this point, the peak current reached its maximum value. However, the peak current tends to decrease as the electrodeposition time is extended to 10 and 15 min. A Similar trend was observed for PEDOT deposited on bare ITO. The change in peak current can be ascribed to the difference in surface morphology of the PEDOT layer as the time increases. This might be attributed to the excessive overlapping and steric effect of the thicker PEDOT-coated layer when the polymerization time increases . TherefoAt 15 min electrodeposition of PEDOT, the surface of PVA-GO/PEDOT15m nanofibers is fully covered with the compact PEDOT layer and partially hindered the electron transfer of redox probes to the active sites of nanofiber Fig. f, therebIn contrast, the CV of PVA-GO/PEDOT5m displays the highest peak current response Fig. c which mRct1) can be associated with the interfacial resistance between the PVA-GO nanofiber with the PEDOT-coated layer, followed by the second semicircle (Rct2) which arises from the charge transfer resistance between the PEDOT and the electrolyte solution in the electrochemical system. A linear line inclined at the lower frequency region is attributed to the semi-infinite diffusion of redox species from the bulk solution to the electrode surface. However, the Nyquist plot of PVA-GO/PEDOT1.0V  due to the overoxidation during the electrodeposition [Rct values as the electrodeposition potential increases , that supposed to appear at the high-frequency region might overlap with the semicircle that denoted by the resistance at PEDOT|electrolyte interface due to the small difference in their time constants. In contrast, PVA-GO/PEDOT5m, PVA-GO/PEDOT10m and PVA-GO/PEDOT15m show two semicircles in the Nyquist plots show two semicircles. The second semicircle, Rct2, at the lower frequency region exhibits a larger arc compared to Rct1 at the higher frequency region. By reviewing the diameter of these two semicircles (Rct1 and Rct2), it shows that the resistance increases at higher deposition time due to an increase in the thickness of the film during electropolymerization  which displays a small value (χ2 = 10−2 to 10−3), indicating that the model is well fitted with the experimental data. The proposed models were constructed using four components. The first component is the Rs, followed by the series combination of CPE and Rct. The equivalent circuits have a diffusion element (T) and the CPE as the last component, which corresponds to the capacitance element. Rs is the resistance of the bulk solution; constant phase element (CPE) is used to represent the non-ideal behavior of the double-layer capacitance and inhomogeneity of the electrode surface. Charge transfer resistance (Rct) is associated with the electron exchange at electrode–electrolyte interface, while the T element in the equivalent circuits refers to the ion diffusion which corresponds to a tangent hyperbolic function.The EIS data were fitted with equivalent electrical circuits Fig.  in orderPVA-GO/PEDOT-conducting nanofibers were successfully prepared by a combination of the electrospinning and electropolymerization methods. The concentration of GO in the polymer solution and the applied voltage during electrospinning process were optimized in order to obtain small diameter, uniform, bead-free, and continuous nanofibrous morphology. A proper coating of PEDOT layers on the surface of PVA-GO nanofibers was carried out at different electropolymerization parameters, and the optimized condition was 1.2 V of electrodeposition potential for 5 min. SEM images and structural analyzes revealed that the conducting polymer, PEDOT was effectively growth and well-coated on the electrospun nanofiber. PVA-GO/PEDOT nanofibers exhibited excellent electrochemical performance that can be used in various applications.


With the rapid accumulation of biological datasets, machine learning methods designed to automate data analysis are urgently needed. In recent years, so-called topic models that originated from the field of natural language processing have been receiving much attention in bioinformatics because of their interpretability. Our aim was to review the application and development of topic models for bioinformatics.This paper starts with the description of a topic model, with a focus on the understanding of topic modeling. A general outline is provided on how to build an application in a topic model and how to develop a topic model. Meanwhile, the literature on application of topic models to biological data was searched and analyzed in depth. According to the types of models and the analogy between the concept of document-topic-word and a biological object (as well as the tasks of a topic model), we categorized the related studies and provided an outlook on the use of topic models for the development of bioinformatics applications.Topic modeling is a useful method  and enhances researchers’ ability to interpret biological information. Nevertheless, due to the lack of topic models optimized for specific biological data, the studies on topic modeling in biological data still have a long and challenging road ahead. We believe that topic models are a promising method for various applications in bioinformatics research. A topic model is a kind of a probabilistic generative model that has been used widely in the field of computer science with a specific focus on text mining and information retrieval in recent years. Since this model was first proposed, it has received a lot of attention and gained widespread interest among researchers in many research fields. So far, besides text mining, there also have been successful applications in the fields of computer vision (Fei–Fei and Perona The origin of a topic model is latent semantic indexing (LSI)  in this corpus. Value wij in the matrix represents the frequency of word i in document j. For example, w3,1 = 1 means that the frequency of the word “pathway” in document d1 is 1.0. It is obvious that the number of words is fixed in a corpus, and the collection of these words constitutes a vocabulary. In short, the corpus is represented by the BoW it contains. A BoW is a simplified representation of a corpus as the input of topic modeling. Likewise, if we want to process biological data rather than a corpus, we also need to represent biological data as a BoW: to specify which is the document and which is the word in the field of biology. For instance, in the problem of genomic sequence classification, La Rosa et al. , and the “topics” were discovered during model training.K is the number of topics.In topic modeling, a “topic” is viewed as a probability distribution over a fixed vocabulary. As an example, Table N × K matrix and a K × V matrix, respectively. The output of a topic model is then obtained in the next two steps.Above all, the key idea behind topic modeling is that documents show multiple topics, and therefore the key question of topic modeling is how to discover a topic distribution over each document and a word distribution over each topic, which represent an First, topic modeling needs to simulate the generative process of documents. Each document is assumed to be generated as follows: for each word in this document, choose a topic assignment and choose the word from the corresponding topic. PLSA and LDA are relatively simple topic models; in particular, other topic modes that appeared in recent years are more or less related to LDA. Therefore, understanding LDA is important for the extended application of topic models. We use PLSA and LDA as examples to describe the generative process in this paper.d denotes the label of a document, z is a topic, w represents a word, and Nd is the number of words in document d. Therefore, P(z|d) denotes the probability of topic z in document d, and P(w|z) means the probability of word w in topic z. Then, for PLSA, the generative procedure for each word in the document is as follows: (a) Randomly choose a topic from the distribution over topics (P(z|d)); (b) randomly choose a word from the corresponding distribution over the vocabulary (P(w|z)). The pseudo-code is as follows:In PLSA, suppose Besides the descriptive approach of the generative process above, a graphical model can also reflect the generative process of documents. As shown in Fig. p(z|d) and p(w|z), are assumed to be multinomial distributions. Thus, the topic distributions in all documents share the common Dirichlet prior d, parameter θd of a multinomial distribution over K topics is constructed from Dirichlet distribution Dir(θd|α). Similarly, for topic k, parameter βk of a multinomial distribution over V words is derived from Dirichlet distribution Dir(βk|η). As a conjugate prior for the multinomial, the Dirichlet distribution is a convenient choice as a prior and can simplify the statistical inference in LDA. Therefore, in PLSA, by contrast, any common prior probability distribution was not specified for p(z|d) andp(w|z). Naturally, there are no In LDA, the two probability distributions, Then, we can summarize LDA as a generative procedure:Likewise, we can use a graphical model to represent LDA, as shown in Fig. As described above, the goal of topic modeling is to automatically discover the topics in a collection of documents. The documents themselves are examined, whereas the topic structure—the topics, per-document topic distributions, and the per-document per-word topic assignments—is hidden structure. The central computational problem for topic modeling is how to use the documents under study to infer the hidden topic structure. This task can be thought of as a “reversal” of the generative process; the task of parameter estimation can be summarized as follows: given the corpus, estimate the posterior distribution of unknown model parameters and hidden variables.n denotes the number of times word w appeared in document d, and log p means the probability of . Then, the maximum likelihood estimator is used to obtain the model parameters (p(z|d), p(w|z)), such as the expectation maximization algorithm (EM)  Moon .K topics z, and a set of N words w that constitute the document is expressed asFor an LDA model, given the parameters Via the joint distribution, we can estimate For model training, the inference algorithm of parameters is based on the generative process or a graph model and is the most complex and important stage in topic modeling. For brevity, however, these methods will not be described in detail. Moreover, if we use only LDA, PLSA, or other existing topic models directly, their inference algorithm of parameters is ready-made, and the tasks that we need to do are construction of data input and parameter initialization.N × K matrix; the other is the word probability distributions over topics, represented by a K × V matrix. “Topics” can be identified by estimating the parameters in the case of known documents. If the number of “topics” was specified as K, then K “topics” could be obtained through model training. After that, the word term space of documents is transformed into “topic” space. It is obvious that “topic” space is smaller than word space (K < V), and moreover, examining a document at the topic level instead of at the word level is beneficial for discovery of meaningful structure of the documents.For PLSA and LDA, the outputs of the model include two matrices: one is the topic probability distributions over documents, represented by an The output of a topic model actually reflects the ability to cluster for the corpus. This is because documents with a similar topic probability distribution can be grouped together. Nonetheless, a topic model is not only a clustering algorithm. In contrast to other black-box algorithms, a topic model can interpret the clustering results by the word probability distributions over topics. Meanwhile, it allows data to come from a mixture of topics rather than from only one topic. These characteristics may be crucial for various applications.The simple PLSA or LDA model offers a powerful tool for discovering and exploiting the hidden “topics” in large document collections. We find that, as probabilistic models, the basic topic models such as LDA can be easily modified for a more complicated application. Therefore, since its introduction, LDA has been extended and adapted in many ways. The major extension models of LDA are summarized below.As an unsupervised learning model, LDA can discover underlying topics in unlabeled data. Nevertheless, “topics” discovered in an unsupervised way may not match the true topics in the data. Therefore, many researchers modified LDA in a supervised learning manner, which can introduce known label information into the topic discovery process.The typical supervised topic models include supervised LDA (sLDA)  was proposed in Li and McCallum    is proposed in Blei and Lafferty . As in tIn LDA, the topics are fixed for the whole corpus, and the number of topics is assumed to be known. Wang and McCallum  proposedIn LDA, both the order and other attributes of documents were not considered. Nonetheless, besides the word occurrence statistics of documents, other document attributes such as author, title, geographic location, and links also provide guidance on “topic” discovery. There were many success stories in this kind of research in recent years.In the author-topic model  can be discovered by topic modeling. This way, topic modeling has been applied, for example, to image classification (Fei–Fei and Perona GensimGensim Rehurek  is a freStanford topic modeling toolbox (TMT)Stanford TMT  provides many freely available open-source packages for topic modeling. These open-source packages have been regularly released at GitHub and include the dynamic topic model in C language, a C implementation of variational EM for LDA, an online variational Bayesian for LDA in the Python language, variational inference for collaborative topic models, a C++ implementation of HDP, online inference for HDP in the Python language, a C++ implementation of sLDA, hLDA, and a C implementation of the CTM.With the development of topic models, several toolkits have appeared for the broad application of these topic models. The toolkits below are mainly used in natural language processing.Above all, topic modeling aims to discover and annotate large datasets with latent “topic” information: Each sample piece of data is a mixture of “topics,” where a “topic” consists of a set of “words” that frequently occur together across the samples. This essence of topic modeling strongly accords with biologists’ interests, which include discovering latent patterns in massive biological data. Hence, in recent years, extensive studies have been conducted in the area of biological-data topic modeling. In this section, we discuss existing studies on topic models applied to bioinformatics. First, the process of selection of articles is described.The selection process involves four steps. For example, first, we search for potentially relevant articles published from 1999 to 2016 in PubMed and Web of Science. In PubMed, the search string is  AND (“topic model” OR “topic modeling”). In Web of Science, the search string is topic: [topic-model OR topic-modeling) AND topic:((biology OR medicine) OR biomedicine]. Second, relevant articles (judging by the title and abstract) are retrieved for more detailed evaluation. Third, we search the bibliographies of relevant articles for additional references. Finally, all the retrieved articles are screened by means of the following inclusion criteria: 1) original research published in English; 2) processing of biological data; and 3) the use of LSI, PLSA, LDA, or other variants of the LDA model. At the same time, we exclude articles that meet the following criterion: the use of a topic model for pure text data. This search strategy identified 30 publications.To conduct an integrative analysis of these 30 articles, we study them on the basis of three themes: the tasks of a topic model, the type of a topic model, and the analogy between document-topic-word and a biological object. These three themes also form the foundation for deep understanding of the use of topic models in bioinformatics and are discussed next.First of all, we place special emphasis on the roles and tasks of a topic model in bioinformatics. By exploring the relevant studies, we found that the tasks of a topic model for biological data are mainly focused on three concepts: biological data clustering analysis, biological data classification, and biological data feature extraction. To illustrate the relation among these three tasks, a diagram is shown in Fig. As discussed in “As shown in Fig. First, many studies have been conducted on the topic modeling of expression microarray data. In these studies, gene-sample in this dataset was likened to word-document, and each sample was modeled as a mixture over latent topics. Rogers et al.  and MasaFor protein interaction data, Sinkkonen et al.  proposedTo query experiments relevant to particular biological questions, Caldas et al.  applied Given a large collection of fluorescent images, Coelho et al.  utilizedFor gene sequence data, the desirable task is to characterize a set of common genomic features shared by the same species. Chen et al. , b analyThe study by Chen et al.  was focuFor genome annotation data, Konietzny et al.  employedLiu et al.  and ZhanIn order to analyze cellular endpoints from in vitro high-content screening (HCS) assays, Bisgin et al.  also intBesides the clustering for unlabeled biological data, a topic model can accomplish classification tasks for labeled biological data. In other words, a topic model can not only discover topics but also make the topics match the true biological labels. Nonetheless, as unsupervised learning models, PLSA and LDA offer no obvious way of incorporating a supervised set into their learning procedure. Therefore, for these types of studies, the LDA model needs to be adapted one way or another.As shown in Fig. First, for expression microarray data, the research subject of studies by Perina et al.  is similFor patient-related texts constructed from clinical and multidimensional genomic measurements, Dawson and Kendziorski  proposedk to be words, and the topics discovered by LDA are assigned taxonomic labels. It is noteworthy that this study is similar to research in Chen et al. . To improve the classification accuracy of discrimination between normal subjects and patients with schizophrenia, Castellani et al.  applied For protein sequence data, Pan et al.  proposedJust as in other studies on expression microarray data  terms is greater than 19,600. If the correspondence between the topics and the GO terms is one to one, then the number of topics may be much greater than the number of words. This condition will yield infinite perplexity in the protein function dataset. Second, as opposed to PLSA or LDA, the function labels of a protein are no longer independent. For example, GO terms are organized as a hierarchical structure such as a DAG in GO, and the number of hierarchies is 15. Therefore, for a protein with hierarchical labels, researchers must consider how to utilize the hierarchical relation between labels to find the corresponding topic for each label. All in all, predicting a protein function by means of a hierarchical multilabel topic model is a challenging and worthwhile task.Topic models provide new exploratory structure for big biological data: the topics are displayed as the most frequent words (as shown in Fig. Overall, for biologists, easy-to-understand visualization of the discovered topics in a user interface is essential for topic modeling. Exploration of an effective interface to biological data and its inferred topic structure are a long-term undertaking.The above studies showed that a topic model can accomplish the task of clustering and classification of biological data. Furthermore, each topic is interpreted as a probability distribution over words. That is, compared with black-box algorithms, a topic model can produce a more understandable result and thus may help a biologist to interpret the finding. Meanwhile, unlike traditional clustering, a topic model allows data to come from a mixture of clusters rather than from a single cluster. These characteristics may be useful in bioinformatics.The studies on application of topic models to bioinformatics are only beginning, and further research on improvement of models will soon become an urgent necessity, especially in bioinformatics. We believe that topic models are a promising method with numerous applications to biomedical research.


Dendrobium genus was reported to contain alkaloid, bibenzyl, fluorenone, phenanthrene, sesquiterpenoid, and phenolic acid, which have biological properties. Our aim was to investigate the protective effect of an aqueous extract of Dendrobium nobile Lindl (DNE) against cisplatin-induced acute kidney injury (AKI). Quantification of four phenolic acids  in DNE was determined using the HPLC-photodiode array method. Possible protective effects against cisplatin-induced nephrotoxicity were investigated using in-vitro  and in-vivo (Sprague Dawley rat) studies. Among the four phenolic acids, 4-hydroxybenzoic acid was the most abundant. In the in-vitro study, DNE pretreatment partially prevented decrement of viability after cisplatin (15 μg/mL) treatment in the both the MTT and crystal violet assays. Moreover, relative to cells treated with cisplatin alone, the DNE (50 μg/mL)-pretreated cells showed a ~30% increase in glutathione levels and a ~15% decrease in reactive oxygen species. The expression of p53 was also decreased in DNE-pretreated cells (p < 0.05). In the in-vivo study, the renal function index decreased to normal levels in groups pretreated with DNE (300 and 500 mg/kg); histopathological alterations and apoptotic cells were also attenuated. Moreover, DNE pretreatment ameliorated oxidative stress in the kidney, as evidenced by recovered antioxidant enzyme levels and decreased lipid peroxidation. DNE, by decreasing oxidative stress, was found to have a protective effect against cisplatin-induced nephrotoxicity. Based on these findings, DNE might be beneficial when treating cisplatin-induced AKI. The incidence of acute kidney injury (AKI) is still rising, and the associated mortality has been largely unchanged over the past two decades . Due to cis-Diammineplatium II dichloride), a platinum-containing anticancer drug, is widely used for the solid cancers such as ovarian, and head and neck carcinomas  using the HPLC-photodiode array (PDA) method, and 2) explore the protective effect of the DNE against cisplatin-induced AKI using both in-vitro and in-vivo models.The aims of the present study were to: 1) determine the phenolic acid compounds in an aqueous extract of ChemicalsD. nobile was purchased from Omniherb . The origin of the sample was confirmed taxonomically by Professor Je-Hyun Lee, Dongguk University, Gyeongju, Republic of Korea. A voucher specimen (NO. KIOM-AO15) was deposited in storage at the Basic Herbal Medicine Research Group, Korea Institute of Oriental Medicine. 4-Hydroxybenzoic acid , syringic acid (≥95.0%), vanillic acid (≥97.0%), cisplatin (≥99.0%), captopril (≥98.0%), and crystal violet solution were purchased from Sigma-Aldrich . Ferulic acid (purity ≥98.0%) was obtained from Wako Pure Chemical Industries, Ltd. . Preparations of DNE and standard solutionD. nobile (60 g) was extracted with distilled water (600 mL) by reflux for 2 h. The extracted solution was filtered through filter paper, evaporated to dryness and freeze-dried (5.19 g). The yield of the water extract obtained was 17.5%. A lyophilized sample (20 mg) was dissolved in distilled water (10 mL) and mixed. The solution was filtered through a SmartPor GHP syringe filter . The stock solutions of the four reference standards were dissolved in methanol (1.0 mg/mL) and stored below 4°C.Dried HPLC analysisA Shimadzu LC-20A HPLC system  with a PDA detector was employed in this study. The data were processed using LCSolution software . The analytical column used for separation was a Gemini C18 column  and was maintained at 40°C. The mobile phases for chromatographic separation were carried out using a gradient elution of solvent A (1.0% v/v aqueous acetic acid) and solvent B (1.0% v/v acetic acid in acetonitrile). The gradient flow of the two-solvent system was as follows: 5% B (0 min), 5-70% B (40 min), 70-100% B (45 min), 100% B (50 min), 100-5% B (55 min), and 5% B (70 min). Analysis was performed at a flow-rate of 1.0 mL/min with a detection wavelength of 254 nm. The injection volume was 10 μL.Cell viability assay4 cells/mL in 96-well plates with regular growth medium. The experiments were carried out on the following day. The effect of DNE on the cisplatin-treated PK15 cells was assessed using MTT and crystal violet assays. PK15 cells were treated with ascorbic acid  and DNE  2 h before cisplatin (15 µg/mL) treatment; after cisplatin treatment, the cells were incubated for 24 h. The MTT assay was performed using the EZ-Cytox Cell Viability assay kit  according to the manufacturer’s protocol. The crystal violet assay was carried out based on a previous report with minor modifications  and the glutathione (GSH) assays, cells were pretreated with ascorbic acid  and DNE (0 and 50 µg/mL). After 2 h, the cells were treated with cisplatin (15 µg/mL) and incubated for 24 h. The ROS contents were determined using the dihydrodichlorofluoroscein diacetate  method with some modification . The levWestern blot of p53PK15 cells were prepared in the same manner as described for the ROS and GSH assays. After incubation, the cells were lysed with lysis buffer . After the protein assay, a 30 µg protein sample was separated using 12% SDS-PAGE. The proteins were transferred onto a nitrocellulose membrane in a Semi-Dry Transfer system from Bio-Rad . After blocking, the membrane was incubated with primary antibody anti-p53 . Horseradish peroxidase-conjugated anti-mouse IgG  was used for p53 detection. Immunoreactivity was visualized using an enhanced chemiluminescence detection kit .Animal studyad libitum. Healthy SD rats (n = 30) were randomly allocated into 6 groups (n = 5/group) and treated for 28 days with each compound orally as follows: group 1 , group 2 , group 3 (100 mg/kg of captopril + cisplatin), groups 4-6 . Captopril, angiotensin-converting enzyme inhibitor, was used as a positive control drug, which is known to alleviate cisplatin-induced nephrotoxicity by its antioxidant properties and renin-angiotensin system inhibitory effect  and creatinine (CRE) were determined on a dry chemistry system . The left kidney was quickly removed for histopathological analysis. The other kidney was removed and used in the GSH  and the malondialdehyde  assays. The assays were conducted according to the manufacturer’s protocol.Four-week-old male Sprague Dawley (SD) rats were obtained from Orient Bio  and acclimated to laboratory conditions  for 1 week before experimentation. All animals were supplied with standard chow  and water y effect , 20. On Histopathological examinationThe left kidney was fixed immediately in a 10% buffered formalin phosphate solution, embedded in paraffin and cut into 5 μm sections and processed for histological staining. These serial tissue sections were either stained with haematoxylin and eosin (H&E) for histopathological examination or subjected to TUNEL staining. Apoptotic nuclei were detected by the TUNEL method using an apoptosis detection kit  according to the manufacturer’s protocol. All of the stained slides were analyzed under the light microscope.Statistical analysisP < 0.05 were considered to be statistically significant.Data are presented as mean values ± standard error of mean (SEM). Significant differences among the experimental groups were determined using the one-way analysis of variance (ANOVA) test followed by Tukey’s post hoc analysis. Values of HPLC analysisr2) of the calibration curves and the identified contents of the phenolic acids in DNE are summarized in In-vitro studyp < 0.05). DNE pretreatment partially recovered viability when compared to cells treated with cisplatin alone; DNE at 50 μg/mL demonstrated the highest viability in the both MTT .In the western blot assay, p53 expression was markedly increased after cisplatin treatment . HoweverIn-vivo studyEffect of DNE on renal physiology and oxidative statusp < 0.05).No adverse effects were observed in the animals during the study. Cisplatin-induced renal function disruption was confirmed in the renal function index. BUN and CRE, and urine volume were significantly increased about 5-, 17-, and 2-fold, respectively, after cisplatin injection . Meanwhip < 0.05). In groups treated with DNE, the MDA level was decreased to about 50%  compared to the group treated with cisplatin alone. These groups also had increased GSH content (p < 0.05).The antioxidant activity of the DNE in cisplatin-induced renal injury was assessed by measuring GSH and MDA levels in the kidney . CisplatEffect of DNE on histopathological alterationp < 0.05).The control group cells had an intact cytoplasm with a normal structure. In contrast, tubular detachments with a broad loss of the brush border were observed in the cells of the cisplatin alone group . In the Dendrobium genus was reported to have an antioxidant effect with radical-scavenging activity  reduced cisplatin-induced histopathological alterations in the region of the proximal tubule. Moreover, DNE pretreatment markedly the decreased TUNEL-positive cell number although the effect was not dose-dependent. in-vitro and in-vivo. DNE treatment enhanced cell viability and ameliorated renal damage by decreasing oxidative stress. Thus, DNE could potentially be used in the prevention of AKI. Further studies are needed to determine the therapeutic window of DNE for clinical application.In the present study, DNE, which contains phenolic acids, was found to have a protective effect against cisplatin-induced nephrotoxicity both


Schizophrenia is a chronic debilitating disorder which affects about 21 million people worldwide (WHO 2017). Elevated pre-synaptic striatal dopamine synthesis capacity is a robust neurochemical alteration seen in patients with schizophrenia compared to controls, with a large effect size Cohen’s d=0.79 . Ketamine, a non-competitive N-methyl-D-aspartate receptor (NMDAR) antagonist induces psychotomimetic effects in healthy human  and exacerbates psychotic symptoms in patients with schizophrenia . For these reasons, it has been used to model the neurochemical alterations seen in schizophrenia such as dopaminergic overactivity . However, the effect of sub-chronic ketamine on dopamine synthesis capacity in vivo is not known. Here we investigated the effect of sub-chronic ketamine on striatal dopamine synthesis capacity in vivo using Positron Emission Tomography (PET) imaging and on locomotor activity in the mouse. Moreover, via a chemogenetics approach (Roth 2016) we explored the role of midbrain dopamine neuron activity in mediating ketamine-induced effects.All procedures were conducted under licence in accordance with the UK Animals (Scientific Procedures) Act of 1986. Mice received a sub-anaesthetic dose of ketamine or an equivalent volume of saline for five consecutive days. Locomotor activity was assessed in the open field test. Moreover, mice received a dynamic 3,4-dihydroxy-6-[(18)F]-fluoro-L-phenylalanine Positron Emission Tomography (PET) scan to assess striatal dopamine synthesis capacity in vivo. Data were analysed using an extended Patlak graphical analysis approach . Further midbrain dopamine neurons were transduced with an adeno-associated virus vector expressing Gi-coupled (hM4Di) inhibitory receptors under the control of the dopamine transporter (DAT) promoter in DATCre positive mice. Standard immunohistochemistry was used to label dopamine neurons and mCherry expression in dopamine neurons was confirmed using confocal microscopy. Two weeks following the stereotaxic injection of the viral construct, mice received clozapine N-oxide (CNO) to study the effects of inhibiting dopamine neuron firing on locomotor activity and striatal dopamine synthesis capacity in the sub-chronic ketamine model. Data were analysed by two-tailed independent samples t-tests, one-way ANOVA and repeated measures two-way ANOVA followed by Bonferroni post hoc tests where appropriate. p<0.05 was considered statistically significant.Sub-chronic ketamine treatment significantly increased striatal dopamine synthesis capacity  and induced locomotor sensitization (p<0.01). hM4Di-mCherry viral construct was successfully transduced in midbrain dopamine neurons with over 98% specificity. Chemogenetic inhibition of midbrain dopamine neurons prevented the ketamine-induced elevation in striatal dopamine synthesis capacity  and locomotor sensitization (p<0.05).Our data show that sub-chronic ketamine results in the elevation in striatal dopamine synthesis capacity and locomotor sensitization and that these effects require midbrain dopamine neuron activation. Furthermore, our data are in support of the hypothesis that NMDA receptor hypofunction on GABAergic interneurons leads to disinhibition of glutamatergic projections and subsequently increase in dopamine neuron activity and dopamine synthesis capacity in projection targets such as the striatum.


The stagnation in drug development for schizophrenia highlights the need for better translation between basic and clinical research. Understanding the neurobiology of schizophrenia presents substantial challenges but a key feature continues to be the involvement of subcortical dopaminergic dysfunction in those with psychotic symptoms. Our contemporary knowledge regarding dopamine dysfunction has clarified where and when dopaminergic alterations may present in schizophrenia. For example, clinical studies have shown patients with schizophrenia show increased presynaptic dopamine function in the associative striatum, rather than the limbic striatum as previously presumed. Furthermore, subjects deemed at high risk of developing schizophrenia show similar presynaptic dopamine abnormalities in the associative striatum. Thus, our view of subcortical dopamine function in schizophrenia continues to evolve as we accommodate this newly acquired information. However, basic research in animal models has been slow to incorporate these clinical findings. For example, psychostimulant-induced locomotion, the commonly utilised phenotype for positive symptoms in rodents, is heavily associated with dopaminergic activation in the limbic striatum. This anatomical misalignment has brought into question how we assess positive symptoms in animal models and represents an opportunity for improved translation between basic and clinical research. The current review focuses on the role of subcortical dopamine dysfunction in psychosis and schizophrenia. We present and discuss alternative phenotypes that may provide a more translational approach to assess the neurobiology of positive symptoms in schizophrenia. Incorporation of recent clinical findings is essential if we are to develop meaningful translational animal models. The onset of psychotic symptoms, which is strongly associated with alterations in dopamine function, is a key feature underpinning a clinical diagnosis7. However, results from clinical research regarding the specific loci of dopamine dysfunction in schizophrenia10, have triggered a reappraisal of our perspective on the neurobiology of schizophrenia. Currently there is a disparity between the tests for positive symptoms in animal models and recent clinical evidence for dopaminergic abnormalities in schizophrenia. Therefore, it is critical that this contemporary clinical knowledge actively influences the agenda in applied basic neuroscience.Our knowledge of the neurobiology of schizophrenia, while still rudimentary, has advanced considerably in recent years. However, these findings have not translated to better treatments for those with schizophrenia. The three primary symptom groups, positive, cognitive and negative Box , have bePositive symptoms: Positive symptoms include delusions and hallucinations, linked to aberrant salience. These symptoms are most recognisable during periods of acute psychosis.Cognitive symptoms: Impairments in learning, memory, attention and executive functioning are all included as cognitive symptoms.Negative symptoms: Negative symptoms include blunting of affect , avolition (deficits in motivation) and social withdrawal.11, it is critical that our understanding and the use of animal models evolves alongside our knowledge of schizophrenia neurobiology. The delayed incorporation of new clinical findings to develop better animal models highlights the need for better communication between clinical and basic research communities.It is widely acknowledged that we cannot recreate the complicated symptom profile of schizophrenia in animal models. However, animal models (the majority and focus of the present article being rodent models) provide an avenue to invasively explore the role of neurotransmitters and circuitry in psychiatric diseases. To improve the poor predictive validity of treatments in animal modelsIn this article, we discuss the challenges clinicians and researchers are facing in understanding the neurobiology of positive symptoms and psychosis in schizophrenia. We discuss the implications this has for current assessments of positive symptoms in rodents and propose a more relevant set of tests for future study. Finally, the need for a joint focus on bi-directional translation between clinical and basic research is outlined.14, but for most people these are transient15. Psychotic symptoms are also not specific to a particular mental disorder16. The clinical efficacy of antipsychotic drugs is heavily correlated with their ability to block subcortical dopamine D2 receptors18, suggesting dopamine signalling is important. In spite of this, no consistent relationship between D2 receptors and the pathophysiology of schizophrenia has emerged20. In contrast, the clinical evidence points towards presynaptic dopamine dysfunction as a mediator of psychosis in schizophrenia19.Psychiatric symptoms exist on continua from normal to pathological, meaning the threshold for diagnosis of schizophrenia in clinical practice can be challenging. The clinical diagnosis of schizophrenia relies heavily on the positive symptoms associated with a prolonged psychotic episode. However, a relatively high percentage of the general population (8–30%) report delusional experiences or hallucinations in their lifetime24. These include the limbic, associative and sensorimotor areas  imaging have shown patients with schizophrenia show increases in subcortical synaptic dopamine content30, abnormally high dopamine release after amphetamine treatment35 and increased basal dopamine synthesis capacity (determined indirectly by increased radiolabelled L-DOPA uptake)37 compared with healthy controls. Increased subcortical dopamine synthesis and release capacity are strongly associated with positive symptoms in patients38, and increased subcortical synaptic dopamine content is predictive of a positive treatment response29. It was widely anticipated that the limbic striatum would be confirmed as the subdivision where these alterations in dopamine function would be localised in patients. The basis for this prediction was the belief that reward systems were aberrant in schizophrenia39. However, as PET imaging resolution improved it was found that increases in synaptic dopamine content10 and synthesis capacity8 were localised, or more pronounced37, in the associative striatum  subjects show increased subcortical synaptic dopamine content48, alterations in cortical inputs to midbrain dopamine systems49 and, although little direct evidence has been observed, developmental alterations in dopamine neurons themselves51. Furthermore, other pathways and/or neurotransmitters may be more critical in treatment-resistant patients52. We propose a network model whereby dysfunction in a central circuit, including the associative striatum, prefrontal cortex and thalamus, is critical for the expression of psychotic symptoms in schizophrenia. This model would suggest that dysfunction in auxiliary circuits  contribute to psychotic symptoms by feeding into this primary network. Ascertaining the role of dopaminergic dysfunction, in the context of networks important for psychotic symptoms in schizophrenia, will provide a better base for constructing objective readouts in basic and clinical research.Several avenues have been proposed to explain a selective increase in associative striatal dopamine function, such as alterations in hippocampal control of dopamine projections53) and delusions. In schizophrenia, auditory hallucinations have been associated with altered connectivity between the hippocampus and thalamus54. During hallucinations, increased activation of the thalamus, striatum and hippocampus have also been observed55. Thus, altered thalamocortical connectivity, especially with the hippocampus, may impede internal/external representations of auditory processing56. In contrast, delusions in people with schizophrenia have been associated with overactivation of the prefrontal cortex (PFC) and diminished deactivation of striatal and thalamic networks57. Thus, the complexity of psychotic symptoms is congruent with the highly connected nature of implicated brain regions.Psychosis is a condition that features a range of behavioural alterations that relate to a loss of contact with reality and a loss of insight. People with psychosis experience hallucinations  is associated with alterations in cortico-striatal networks. For example, people with basal ganglia or caudate lesions can present with both hallucinations and delusions61. Furthermore, a case study of religious delusions in a patient with temporal lobe epilepsy was associated with overactivity of the PFC62, and there are multiple lines of evidence suggesting that the PFC is integral for delusionary beliefs63. Therefore, while impairing networks specific to certain sensory modalities can lead to hallucinations, dysfunctional integration of PFC input to the associative striatum may be especially important for delusional symptoms in schizophrenia.Although we still know little about the underlying neurobiology of psychosis, focal brain lesions allow for a better understanding of the networks involved without the confounds of medication and unrelated neuropathology. Generally speaking, lesions that induce hallucinations are often in the brain networks associated with the stimulus of the hallucination 64. Brain imaging studies have demonstrated that medication-naive patients with schizophrenia have significantly reduced thalamic and caudate volumes relative to healthy controls and medicated patients65. Moreover, reduced thalamic volumes has also been observed in UHR subjects66. A simplified schematic of the networks that may be especially relevant to psychotic symptoms in schizophrenia is presented in Fig. Central to the networks involved in psychosis and schizophrenia, the thalamus acts as a relay for most information going to the cortex67; therefore, excessive D2 signalling in the associative striatum appears to be critical. Stimulation of D2 and D1 receptor expressing medium spiny neurons (which are largely segregated68) in the associative striatum feedback indirectly to the thalamus, completing a loop that allows for feedforward-based and feedback-based signalling. The basal ganglia acts as a gateway for, or mediator of, cortical inputs71 and may represent a common pathway through which psychotic symptoms present. Therefore, excessive dopamine signalling in the associative striatum may directly lead to psychotic symptoms by compromising the integration of cortical inputs. In treatment-responsive patients, antipsychotics may attenuate the expression of psychotic symptoms by normalising excessive D2 signalling29 to restore the balance between D1 and D2 receptor pathways72. Because they act downstream to schizophrenia-related presynaptic abnormalities, they fail to improve indices of cortical function . Alternatively, impaired cortical input to the associative striatum via the thalamus, PFC or other regions could dysregulate this system independently of, or in addition to, associative striatal dopamine dysfunction. In this case, D2 receptor blockade may be insufficient to restore normal function, which is one explanation for why some individuals are treatment refractory. For example, increases in subcortical synaptic dopamine content29 and increases in presynaptic striatal dopamine function52 are both associated with increased treatment efficacy. Thus, in treatment-resistant subjects, there is little evidence of abnormal dopaminergic function52. Medicated persons with schizophrenia, who remain symptomatic with auditory hallucinations, show increased thalamic, striatal and hippocampal activation55. Moreover, treatment-refractory patients who respond positively to clozapine treatment show alterations in cerebral blood flow in fronto-striato-thalamic circuitry, suggesting clozapine is restoring a functional imbalance in these systems73. Taken together, this evidence suggests that psychosis is the result of a network dysfunction that includes a variety of brain regions (and multiple neurotransmitter-specific pathways), of which impairment at any level could precipitate psychotic symptoms.This raises important questions as to how antipsychotic drugs exert their effects. In most individuals with schizophrenia, antipsychotic treatment is effective in reducing positive symptoms74, there is a little evidence for subcortical hyperdopaminergia playing a direct role in the cognitive impairments observed in schizophrenia. Furthermore, antipsychotic treatments do not improve patient’s cognitive function75. There is a mounting evidence that cognitive symptoms may present prior to positive symptoms in schizophrenia76. Given brain networks involved in hallucinations and delusions all involve cortical regions, the underlying pathology causing cognitive symptoms may also contribute to psychotic symptoms. Thus, in some cases psychosis may represent the summation of broad cognitive impairments inducing local network dysfunction  for psychosis in patients. The most commonly used behavioural assessments of positive symptoms in animal models include enhanced amphetamine-induced locomotion and deficits in prepulse inhibition (PPI)81. These tests are widely used because they are relatively simple to perform. However, we propose that given current knowledge of the neurobiology in schizophrenia, they have outlived their usefulness as measures of positive symptoms.Potentially, the most useful avenue for animal models to assist in schizophrenia research will be identifying convergent aetiological pathways38 and rats82. Amphetamine-related behaviours in rodents are also strongly linked to activity in striatal brain regions83. Thus, an increased locomotor response to amphetamine  is considered a simple test to reflect the subcortical hyperdopaminergia underlying the psychotic symptoms in schizophrenia. Most animal models of schizophrenia report increased locomotor activation after psychostimulants78. However, the recent clinical evidence described above suggests that current assessments of animal models does not reflect contemporaneous knowledge of dopamine activity in those with schizophrenia.Amphetamine increases dopamine release in striatal brain regions of both humans87 or dopamine89 into the nucleus accumbens induces locomotion. Furthermore, blocking dopamine signalling in the nucleus accumbens attenuates amphetamine-induced locomotion90. Specifically activating limbic dopamine projections using chemogenetic tools robustly increases locomotion, but activating associative dopamine projections does not91. Thus, there is an anatomical misalignment between the primary behavioural outcome deemed important for positive symptoms in animal models of schizophrenia , and clinical evidence in patients . Furthermore, clinical studies directly comparing activity levels in patients with schizophrenia and bipolar disorder suggest that hyperactivity may be a core feature of bipolar disorder rather than schizophrenia92.The relative contribution of specific dopamine pathways to amphetamine-induced locomotion provides a good example of why a paradigm shift is required for research using animal models for positive symptoms in schizophrenia. For example, amphetamine-induced locomotion is largely driven by limbic dopamine release. Local administration of amphetamineOne argument for amphetamine-induced locomotion is that it is predictive of antipsychotic efficacy, but this is merely a serendipitous side effect. Systemically administered amphetamine increases dopamine function in both the limbic striatum (locomotion) and associative striatum (positive symptoms). Systemically administered antipsychotics antagonise D2 receptors throughout the brain. Therefore, amphetamine-induced locomotion acts serendipitously to predict antipsychotic effectiveness via dopamine release in a parallel circuit (limbic vs. associative dopamine). Optimally, antipsychotics that diminish dopamine signalling preferentially in the associative, rather than the limbic, striatum need to be developed. Obviously, amphetamine-induced locomotion would not be predictive for the latter treatment options.94. Deficits in PPI may reflect an inability to gate out irrelevant information. PPI deficits also respond to antipsychotics but are not specific to schizophrenia94. Thus, PPI deficits do not represent a specific or diagnostic trait of schizophrenia. Intact cortical and striatal function are critical for PPI95 and, therefore, deficits in PPI also reflect an interface between positive and cognitive symptom groups81.One of the most consistently observed neurological impairments in schizophrenia is impaired sensorimotor gating in the form of decreased PPI95, though the associative striatum has also been implicated97. Thus, PPI deficits clearly lack specificity concerning the hyperdopaminergia observed in schizophrenia. Therefore, when assessing rodent models, PPI impairments alone are insufficient for determining positive symptom phenotypes and their predictive validity suffers from the same criticism as that of amphetamine-induced locomotion .PPI is assessed almost identically in rodents and humans and, therefore, is one of the most widely studied deficits in schizophrenia. In rodents, the contribution of limbic dopamine projections to PPI are well-knownClearly, alternative behavioural phenotypes in animal models, consistent with the underlying neuroanatomical/biological features of schizophrenia, need to be established. This does not invalidate our current rodent models; it just emphasises that, in light of the recent compelling PET evidence in patients, we need to review their relevance to the positive symptoms of schizophrenia. Psychosis, an extremely ‘human’ syndrome, will never be truly observable in rodents. However, we can, and should, aim to establish more translationally relevant tests for the underlying neurobiology of psychosis. Ultimately, we need better behavioural tests for positive symptoms in animal models that will lead to therapies efficacious for both positive and cognitive symptoms in patients. We contend that tests aimed at understanding associative striatal function are imperative. We propose that a combination of cognitive behavioural tasks, that can be tested similarly in humans and rodents Fig. , represe100 and can be assessed using near identical behavioural paradigms in both humans101 and rodents102  but rather, reflected an inability to use this information to direct choice101.Goal-directed behaviour is critical for understanding the relationship between actions and their consequences in both humans and rodents. Moreover, goal-directed action heavily depends on the function of the associative striatum102 Fig. . To testtum Fig. . Impairm106 which can be tested similarly in humans and rodents Fig. . Extensi106Fig. . For exa109 or chemogenetics110 mean the field is at a point now where we can focus on particular brain regions and circuits. The proposed tasks, outcome-specific devaluation and serial reversal learning, provide a potential mechanism to focus on associative striatal function , whereas the clinical studies tested a differing working memory construct, memory span capacity . Other factors such as medication history118 may also interfere with the effectiveness of translation between preclinical and clinical studies. To improve translational schizophrenia research it is imperative that we build better avenues for communication between basic and clinical research teams to avoid the aforementioned issues.It is also imperative that basic and clinical researchers maintain active collaborations to prevent the misinterpretation or mistranslation of animal studies. For example, based on the work in monkeys and rodentsComplex syndromes like schizophrenia require a constant reformulation and evolution of ideas and strategies that cannot be achieved by either basic or clinical research in isolation. Clinically, the point at which psychotic symptoms become apparent has dictated our primary diagnostic criteria. Furthermore, it has become evident that a range of complex symptoms emerge before this diagnostic time point. Clinical research must continue to elucidate the features associated with the development of psychosis and better inform a patient’s clinical trajectory throughout the course of schizophrenia. However, our current ability to model psychotic symptoms in animal models is at best questionable and based on historical presumptions rather than recent clinical evidence. Thus, it is imperative that basic research using animal models develops objective measures for the neurobiology underlying psychosis in schizophrenia. Understanding in detail the neurobiological processes that precede these behavioural abnormalities, an avenue of research that cannot be conducted in humans, now becomes a priority. It is only by a synthesis of such approaches that novel therapeutic targets and treatments will emerge.


Disrupted-in-Schizophrenia 1 (DISC1) is a gene known as a risk factor for mental illnesses possibly associated with dopamine impairments. DISC1 is a scaffold protein interacting with proteins involved in the dopamine system. Here we summarise the impact of DISC1 disruption on the dopamine system in animal models, considering its effects on presynaptic dopaminergic function  and postsynaptic dopaminergic function . Our findings show that many but not all DISC1 models display (1) increased locomotion after amphetamine administration, (2) increased dopamine levels after amphetamine administration in the nucleus accumbens, and (3) inconsistent basal dopamine levels, dopamine receptor levels and binding potentials. There is also limited evidence for decreased tyrosine hydroxylase levels in the frontal cortex and increased dopamine transporter levels in the striatum but not nucleus accumbens, but these conclusions warrant further replication. The main dopaminergic findings are seen across different DISC1 models, providing convergent evidence that DISC1 has a role in regulating dopaminergic function. These results implicate dopaminergic dysregulation as a mechanism underlying the increased rate of schizophrenia seen in DISC1 variant carriers, and provide insights into how DISC1, and potentially DISC1-interacting proteins such as AKT and GSK-3, could be used as novel therapeutic targets for schizophrenia. Disrupted-in-Schizophrenia 1 (DISC1) gene was originally discovered at the breakpoint of a balanced translocation t  in a Scottish family and later identified in a North American family with high rates of schizophrenia.4 Since then, preclinical models have shown that DISC1 mutant animals exhibit behavioural, neurostructural and neurochemical features relevant to schizophrenia, 6 although its significance for the human disease has been debated.9 DISC1 is described as a scaffold protein with multiple interactors involved in a wide range of cellular processes including neurotransmitter signalling.11 In particular, DISC1 is known to interact with several proteins involved in dopamine signalling including fasciculation and elongation protein zeta 1, phosphodiesterase 4D9 and phosphodiesterase 4B, serine/threonine protein kinase Akt and glycogen synthase kinase-3 (GSK-3)16 as well as synaptic interactors such as kalirin-7 and the Traf2, Nck-interacting kinase,18 and the microtubule/centrosomal proteins pericentriolar material 1 and Bardet–Biedl syndrome protein.20 These multiple interactions have highlighted the potential of DISC1 as a therapeutic target.23The 26 The dopamine hypothesis of schizophrenia was initially based on the findings that the affinity of antipsychotic medications for dopamine receptors is closely related to their clinical potency,29 and that drugs that increase dopamine levels provoke psychotic symptoms in healthy people.31 Molecular imaging studies since then have shown increased presynaptic dopamine synthesis capacity and release in schizophrenia35 and in subjects with prodromal symptoms of schizophrenia.39 Alterations in dopamine D1 and D2/3 receptors, tyrosine hydroxylase (TH) levels and baseline synaptic dopamine levels in schizophrenia have also been reported,41 although with some inconsistency.42The neurotransmitter dopamine is widely thought to have a central role in the aetiology of psychotic disorders.DISC1 pathway alterations may impact on dopaminergic function, as it has not been comprehensively synthesised before. The aim of our review was therefore to summarise the impact of DISC1 on TH levels, dopamine transporter (DAT) levels, basal dopamine levels and after amphetamine administration, dopamine D2 receptor-binding potential (BP), dopamine D1 (D1R) and D2 receptor (D2R) levels, and locomotor activity after amphetamine administration for dopamine-related behaviour.43 We selected publications citing data collection in the midbrain, as this is the location of the majority of dopaminergic neuron cell bodies in the brain, and the frontal cortex, hippocampus and striatum as these are the target sites of the main dopaminergic pathways relevant to psychiatric disorders.45These findings highlight why dopaminergic dysfunction has a pivotal role in schizophrenia. In view of this, we sought to review the evidence from animal models that DISC1') AND . Only articles meeting the following criteria were included: (1) original studies; (2) English language; (3) peer-review journals; (4) findings reporting TH levels, DAT levels, basal dopamine levels and/or dopamine levels after amphetamine administration, and/or dopamine receptor-binding potential, dopamine receptor levels and/or locomotion after amphetamine administration in a DISC1 model compared with a control group; and (5) in the frontal cortex, striatum, nucleus accumbens, midbrain and/or hippocampus, as these regions are major target sites of dopaminergic projections in the brain and are thought to be involved in the pathophysiology of schizophrenia.45 The DISC1 models were selected based on gene mutation in DISC1 or alteration in the quantitative expression of DISC1 protein. Method and results sections of the eligible articles were screened to identify the measures of interest listed above.The entire PubMed database was searched to select publications. Studies were screened based on the terms (‘Disrupted-in-Schizophrenia-1' OR ‘DISC1 models and controls in (1) TH levels; (2) DAT levels; (3) basal dopamine levels; (4) dopamine levels after amphetamine administration; (5) dopamine receptor-binding potential; (6) D1R and D2R levels; and (7) locomotion after amphetamine administration. In addition, the following data were extracted: (8) authors; (9) year of publication; (10) the DISC1 model; (11) samples size; and (12) methods. The data were extracted by TD and checked by SVT. Findings related to the nucleus accumbens and olfactory tubercle were merged as both being part of the ventral striatum.46The main outcome measures were the differences between the DISC1 model used, sample sizes and methods. It should be noted that we were not able to find evidence that dopaminergic function had been investigated in more recently disclosed DISC1 models, for example.48Fifty-one studies were excluded from a total of 65 studies screened . FourteeDISC1 models were identified across the studies as follows: (1) transgenic expression of truncated human Disc1 protein with dominant-negative (DN) effect; (2) DISC1 haploinsufficiency/silencing; (3) full-length human DISC1 overexpression; (4) artificial Disc1 mutation; and (5) wild-type model  and genotype effect in a stress condition (isolated wild type versus isolated transgenics) were included from Niwa et al.51Five types of pe model . Data onhDISC1 and the Disc1 RNA interference (RNAi)/silencing models compared with controls.54 These studies showed reduced TH levels in frontal cortical regions in isolated hDISC1 mice compared with isolated controls51 and in the Disc1 RNAi/silencing model compared with controls54  were used, measuring extracellular and total dopamine levels, respectively.Nine studies investigated basal dopamine levels in 61 and two using both post-mortem HPLC-ED and microdialysis.54 One of the two studies using microdialysis showed decreased basal dopamine levels in the Disc1 RNAi/silencing model compared to controls,54 whereas the other study found no significant changes between the hDISC1 mice and controls and the isolated hDISC1 mice and isolated controls.51 For HPLC-ED, decreased basal dopamine levels were found at postnatal day 56 in the Disc1 RNAi/silencing model,54 and in males from the prenatal hDISC1 expression group (until embryonic day 17), the postnatal expression group (from embryonic day 17 on) groups and the pre- and postnatal hDISC1 expression (entire life) compared with controls.49 No significant differences were reported in the other studies.61Eight studies investigated basal dopamine levels in the frontal cortex/mPFC, six using HPLC-ED61 and one using both HPLC-ED and microdialysis.59 One study found decreased total dopamine levels in the full-length DISC1-overexpressing rat model compared with controls in the dorsal striatum.58Six studies investigated basal dopamine levels in the striatum using HPLC-EDin vivo microdialysis,52 four using HPLC-ED61 and one using both techniques.54 Two studies using in vivo microdialysis showed decreased basal dopamine levels in the Disc1 RNAi/silencing model compared with controls54 and the hDISC1 heterozygous line 10 and 37 mice compared with controls.52 One study using HPLC-ED showed significant decreased basal dopamine levels in L100P ENU-generated missense mutation mice,61 whereas the others found no significant differences.59Six studies investigated basal dopamine levels in the nucleus accumbens, one using Disc1Δ2–3 haploinsufficiency model and controls.55One study investigated basal dopamine levels in the midbrain and found no significant difference between the 61 One study found decreased dopamine levels in females in the postnatal hDISC1 expression group compared with prenatal expression only and controls.49 The other studies found no significant differences.61Seven studies investigated basal dopamine levels in the hippocampus using HPLC-ED.51 and one using HPLC-ED.50All the studies induced dopamine release by administrating amphetamine-related drugs. Two studies investigated induced dopamine release in the frontal cortex and found no significant differences, one using microdialysisin vivo microdialysis59 and one study using HPLC-ED,50 both reporting no significant differences.One study investigated induced dopamine release in the striatum using 56 The four studies found significantly increased dopamine release. This was in the DISC1 knockdown compared with controls,54 in isolated hDISC1 compared with isolated controls,51 in heterozygous line 10 and 37 compared with controls 52 and female but not male Disc1Δ2–3 mice compared with controls.56Four studies investigated induced dopamine release in the nucleus accumbens using microdialysis.hDISC1 and controls.50One study investigated induced dopamine release in the hippocampus using HPLC-ED and found no significant difference between the hDISC1 and controls, and the Disc1Δ2–3 haploinsufficiency model and controls.56Two studies investigated D1R levels in the frontal cortex and found no significant differences between the 58 One study found increased levels in the hDISC1 model compared with controls,52 whereas the others found no significant differences.58Three studies investigated D1R levels in the striatum.56 One study found significant increased D1R levels in female and no significant changes in male and mixed Disc1Δ2–3 groups,56 whereas the other showed no significant differences.51Two studies investigated D1R levels in the nucleus accumbens.56 One study found significant increased D2R levels in the hDISC1 mice compared with controls and isolated hDISC1 mice compared with isolated controls51 and the two other studies found no significant differences between the Disc1 RNAi/silencing/haploinsufficiency models and controls.56Three studies investigated D2R levels in the frontal cortex.56 The hDISC1 mice showed significant increased D2R levels,52 whereas the other showed no significant differences between the Disc1Δ2–3 models and controls.56Two studies investigated D2R levels in the striatum.59 The dopamine D2 receptor is known to exist in two interconverting states, a low-affinity (μm) and a high-affinity (nm) state.63 Lipina et al.59 and Trossbach et al.58 found a significant increase in dopamine D2 high-affinity receptor levels using [3H]domperidone binding challenged with dopamine, but Trossbach et al. found no difference in [3H]raclopride binding by autoradiography. As raclopride does not distinguish low from high affinity or D2 from D3 receptors, taken together, these studies are consistent with a shift to the high-affinity state without a change in total D2/3 receptor levels. Jaaro-Peled et al.52 found significantly increased binding potential of D2/3 receptor availability in the striatum using [11C]raclopride PET and significantly increased levels of D2/3R in the medial part of the right rostral striatum using [3H]spiperone autoradiography but no significant differences in D2/3 levels in the total right rostral striatum and the lateral part of the right striatum in the hDISC1 compared with controls. Pogorelov et al.50 found no significant difference in the rostral part of the striatum using [11C]raclopride autoradiography in the hDISC1 mice compared with controls.Four studies investigated dopamine receptor-binding potential in the striatum.56 One study found significantly increased D2R levels in female but not male and mixed Disc1Δ2–3 groups,56 whereas the other showed no significant differences.51Two studies investigated D2R levels in the nucleus accumbens.11C]raclopride autoradiography PET and found no significant differences in the nucleus accumbens but significantly decreased levels in the right olfactory tubercle of female hDISC1 mice compared with controls.50 They used the same approach to investigate D2/3R-binding potential using [11C]raclopride autoradiography in the midbrain (substantia nigra/VTA) and found no significant difference between the hDISC1 and controls.50One study investigated D2/3R-binding potential in the nucleus accumbens using [Disc1Δ2–3 haploinsufficiency and controls.56One study investigated D2R levels in the hippocampus and found no significant difference between the 62 Ten studies found increased locomotion after amphetamine administration in the DISC1 models compared with control animals, in the pre- and postnatal hDISC1 expression groups,49hDISC1 mice,52 the Disc1 RNAi/silencing model,54 female but not male Disc1Δ2–3 mice,55 male but not female Disc1Δ2–3 mice,56 full-length hDISC1-overexpressing rats,58Disc1-L100P mice,59 isolated hDISC1 mice compared with isolated controls51 and wild-type Disc1 mice with no DISC1–D2R disruption.62 Two studies found decreased locomotion after amphetamine administration, in female but not male hDISC1 mice after escalating dose of methamphetamine treatment compared with controls in Pogorelov et al.50 and wild-type mice with Disc1–D2R disruption in Su et al.62 No significant changes were found in the hDISC1 mice and Disc1-L100P/L100P mice compared with controls in three studies.60Thirteen studies investigated locomotion after amphetamine administration.DISC1 models exhibit reasonably consistent (1) increased locomotion after amphetamine administration (2) increased dopamine levels after amphetamine administration in the nucleus accumbens but (3) inconsistent alterations in basal dopamine levels and dopamine receptor levels and binding potentials. These findings extend other studies showing increased methamphetamine-induced dopamine release in the nucleus accumbens and locomotor hyperactivity in mice lacking DISC1-interacting proteins, such as fasciculation and elongation protein zeta 164 and PDE4,65 to indicate that the DISC1 pathway affects specific aspects of dopaminergic function.The main findings show that compared with controls, the DISC1 models  the presynaptic effects of DISC1 on dopamine release in the nucleus accumbens or (2) a direct impact of the DISC1 models on postsynaptic dopaminergic signal transduction, such as the protein serine/threonine protein kinase (Akt)–glycogen synthase kinase-3 (GSK-3) pathway. In support of the first hypothesis, the nucleus accumbens is thought to have an important role in regulating locomotor activity.70 Local administration of dopamine and amphetamine has been shown to induce hyperactivity similar to systemic administration,72 and our review has identified reasonably consistent evidence that DISC1 models are associated with greater dopamine release to amphetamine. With regards to the second hypothesis, Akt and GSK-3 are two proteins regulated by DISC1 with respectively indirect and direct interactions.73 The Akt–GSK-3 pathway modulates dopamine neurotransmission and amphetamine-mediated locomotor activity.76 Amphetamine/methamphetamine-induced dopamine release decreases Akt activation (phosphorylation state77), which activates GSK-3 by dephosphorylating the Serine 9 site78 to modulate dopamine-dependent behaviours.74 Although Disc1 wild-type protein decreases Akt and GSK-3 activation,79 the impact of mutant DISC1 on Akt and GSK-3 is less clear. Evidence shows increased and decreased Akt activation in DISC1 knockdown,80 no effects on Akt and GSK-3 levels in hDISC1 mice50 and consistently increased GSK-3 activation in DISC1 knockdown and Disc1 point mutation Q31L.82 Interestingly, mice overexpressing GSK-3 develop locomotor hyperactivity,83GSK-3 knockdown mice express reduced locomotor activity84 and administration of GSK-3 inhibitor decreases amphetamine-induced hyperactivity.85The majority of the Disc1Δ2–3 haploinsufficiency,56 a DN hDISC1 model in combination with adolescent isolation stress,51 a transient knockdown in prefrontal cortex 54 and a DN hDISC1 model targeting specifically pyramidal neurons of the cortex and hippocampus.52 This raises the questions of (1) the time course of changes in dopamine and whether there are developmental periods that are particularly vulnerable to DISC1 alterations, (2) the brain regions minimally required to lead to increased dopamine release to amphetamine, and in particular, the role of the cortical regions in regulating the nucleus accumbens dopamine levels.The studies reporting increased dopamine levels following amphetamine administration in the nucleus accumbens used a 86 These findings are in line with evidence showing that adolescence is a critical time life for the development of psychotic disorders including schizophrenia.87 With regards to the second point, a possible mechanism underlying increased dopamine levels in the nucleus accumbens could be a reduction in cortical parvalbumin-positive interneurons. Supporting this, studies have shown a decreased number of parvalbumin-positive interneurons in the cortex of DN DISC1 models.90 Parvalbumin-positive interneurons are GABAergic inhibitory neurons thought to regulate the dopaminergic activity in the nucleus accumbens and to have a role in schizophrenia through the modulation of cortical glutamate excitatory pyramidal neurons.93 Finally, the specific localisation of the findings in the nucleus accumbens might be related to an increased sensitivity of this region to stimulants, as it has been shown to release more dopamine following amphetamine administration compared with other striatal subdivisions.94With regards to the first point, recent studies suggest that DISC1 alterations interact with stress to impact on dopaminergic neurons during adolescence.DISC1 models used  increased locomotion after amphetamine administration and (2) increased dopamine levels after amphetamine administration in the nucleus accumbens but (3) inconsistent basal dopamine levels and dopamine receptor levels and binding potentials. This suggests that presynaptic dopamine dysregulation is a potential mechanism for the increased rates of psychotic disorders seen in the original DISC1 families and DISC1 variant carriers, and identifies a number of potential therapeutic targets for treating or even preventing schizophrenia based on the DISC1 pathway.Compared with controls, the majority of the