In this study, C@Bi2S3 core-shell heterostructures with enhanced supercapacitor performance were synthesized via sacrificial- template-free one-pot-synthesis method. The highest specific capacities of the C@Bi2S3 core shell was 333.43 F g−1 at a current density of 1 A g−1. Core-shell-structured C@Bi2S3 exhibits 1.86 times higher photocatalytic H2 production than the pristine Bi2S3 under simulated solar light irradiation. This core-shell feature of C@Bi2S3 provides efficient charge separation and transfer owing to the formed heterojunction and a short radial transfer path, thus efficiently diminishing the charge recombination; it also facilitates plenty of active sites for the hydrogen evolution reaction owing to its mesoporous nature. These outcomes will open opportunities for developing low-cost and noble-metal-free efficient electrode materials for water splitting and supercapacitor applications.Core-shell heterostructures have attracted considerable attention owing to their unique properties and broad range of applications in lithium ion batteries, supercapacitors, and catalysis. Conversely, the effective synthesis of Bi In addition, supercapacitors are safer and have a lesser environmental impact than batteries3. Mainly, the specific capacitance of a supercapacitor depends on the electrode materials and thus, electrode materials of supercapacitors play an important role. There are several electrode materials available for supercapacitors; the most common are carbon materials owing to their high conductivity, large specific surface area, different forms, and abundance. However, their activity is not sufficient, owing to their low specific energy. In addition, the inset surface of carbon materials makes it difficult for electrolytes to further penetrate the internal layers of carbon4. Different approaches have been employed to overcome these issues like introduction of metal oxides, hetero atoms, and coupling of two or more materials.Active supercapacitors are a class of energy storage devices that have fascinated the scientific community owing to their high power capacity with long cycle life, low cost, and low maintenance. Recently, supercapacitors are being widely used in memory backup, consumer electronics, and industrial power management5. Among the various heterostructure features, core-shell structures exhibit superior performances owing to the combined effects of cores and shells7. Meanwhile, metal sulfides including nickel sulfides, cobalt sulfides, and bismuth disulfides are very important semiconductor materials and have been employed to develop supercapacitor electrodes11. Among these, bismuth sulfide (Bi2S3) has a lamellar structure with a 1.3–1.7 eV direct band gap and these features offers potential applications in the field of thermoelectric cooler devices12, lithium-ion batteries13, and optoelectronic devices14 owing to the possibility of band gap tuning with different sizes of the subcomponent. As the above-mentioned properties strongly rely on the size, shape and morphologies, diverse strategies are put forth to controlled synthesis of bismuth sulfide nanostructured materials. Several Bi2S3 nanomaterials like nano rods, tubes, wires, ribbons are prepared by various synthesis procedures. However, Bi2S3 as an electrode material possesses low conductivity as well as high volume expansion during the charge and discharge cycling, which are major challenges. In addition, the reversible specific capacity fades rapidly during cycling reactions in metal sulfides. This capacitance loss is mainly because of the volume expansion during the charge and discharge processes causing particle cracks and pulverization that breakdown the electrical contacts in the bismuth sulfide anode. Hence, improving the number of charge discharge cycles is a crucial task to address for the optimization of Bi2S3 based anode materials for supercapacitor applications.In recent years, heterostructure nanomaterials comprising two or three different functionalities showed enhanced or different physicochemical performances compared to single functionality materials16. Recently, Yang et al.17 fabricated strongly coupled Bi2S3 nanocrystals anchored on carbon nanotube (CNT) backbones; the resulting Bi2S3@CNT enhanced the conductivity. Zhang et al.18 fabricated composites with CNTs twined with Bi2S3 microspheres using a facile reflux synthetic route, and the CNTs@Bi2S3 composite electrode showed a reversible specific capacity of 247.9 mA h g−1 after 50 cycles. Jung et al.19 and Jin et al.20 developed carbon-coated Bi2S3 crystallites as electrode materials; the specific capacity and cyclability of C@Bi2S3 hybrid were significantly enhanced compared to pristine Bi2S3. However, many well-known electrode materials with unique structural integrity for supercapacitor applications remain unexplored to enhance the specific capacitance. Continuing with the development of carbon nanomaterials, graphene and CNTs are often referred to as supercapacitors owing to their high electron-storage capacities and good electrical conductivity22.To overcome these drawbacks, different methods have been followed to enhance its electrochemical activity; one of the most efficient ways is to design nanohybrids with a core-shell structure using the allotropes of carbon materials, which can act as a projective/buffer layer to improve the volume expansion during charge and discharge processes2 production. Recently, the enhanced photocatalytic activity of Bi2S3-based composites were explored for photocatalytic hydrogen production25. Kadam et al.26 reported a Bi2S3 quantum dot/glass composite that demonstrated efficient hydrogen production (6418.8 μmol h−1 g−1) under solar light irradiation. Feng et al.27 reported carbon-coated Co9S8 nanoparticles as electrocatalysts for water splitting with trithiocyanuric acid as a surfactant for the formation of core-shell structures. However, surfactant- or sacrificial- template-free synthetic procedures remains a challenge, offering scope for the rational design of high-performance core-shell heterostructures.Visible-light-driven photocatalytic reforming of biomass-derived feedstock is a sustainable, renewable, and cost-effective method for H2S3 nanorods, formed as a core-shell heterostructure via a facile and simple one-step hydrothermal reaction. The resulting C@Bi2S3 core-shell heterostructures contain well-defined cross linkages between the Bi2S3 core and carbon shell. These highly porous structures allow the free permeation of electrolyte ensuring rapid movement of ions. Also, the carbon shell on the Bi2S3 core acts an additive effectually shielding the mechanical strain during the charge discharge processes. Moreover, the crosslinked assemblies in the C@Bi2S3 core-shell heterostructures facilitates charge transfer through multipath electron transfer, which could accelerate the electrochemical processes to enhance high energy storage and photocatalytic H2 evolution features.In this work, we have attempted and reported a rational assembly of carbon on the surface of Bi2S3, the Bi2S3 was initially synthesized as described below using a modified hydrothermal method from previously reported literature28. In detail, Bi(NO3)3·5H2O (0.2 M) is dissolved in 25 mL of deionized (DI) water in a glass beaker with vigorous stirring, and a mixture of sodium sulfide (Na2S·9H2O) (0.3 M) and 36 mL H2O2 was added drop by drop into the above solution at 90 °C with continuous stirring for 1 h. Then, it is transferred to a Teflon-lined autoclave and maintained at 190 °C for 6 h. Once it is cooled to room temperature naturally, the product was collected by centrifuging at 6000 rpm, and then was washed three times with ethanol. Then, the product was dried in a vacuum oven at 100 °C for 3 h.To develop the final C@Bi2S3, 5 mg of the as-prepared Bi2S3 was added in 30 mL ethanol and stirred to ensure homogenous mixing. Then, 15 mL of D-glucose solution (0.02 M) was mixed with the above solution, followed by continuous stirring for 60 min, and then transferred into a Teflon-lined stainless-steel autoclave and maintained at 190 °C for 6 h, and then cooled to room temperature naturally. The effect of hold time was explored by interrupting the shell growth at different times: 4, 6, 8, and 12 h, with the other parameters kept constant. Finally, the products were washed thoroughly with ethanol and water thrice and dried at 100 °C for 3 h. The schematic of the preparation procedures for the C@Bi2S3 is presented in Fig. In a typical synthetic procedure for C@Bi−1 in the spectral range of 4000–400 cm−1 using 32 scans. Raman spectra were verified using a Jobin-Yvon Horiba (Lab Ram HR-800) single monochromator attached with a Peltier-cooled charged coupled device (CCD) and used 532 nm Argon (Ar+) laser excitation source at 25 °C under back scattering geometry.The as-synthesized samples were characterized by X-ray powder diffraction (XRD) using a Shimadzu Labx X-ray diffractometer, XRD 6100 model. The XRD patterns of the samples were obtained using Cu Kα radiation (λ = 0.154 nm) at 40 kV and 30 mA. Transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) observations were performed with a Hitachi H-7000 at 110 kV and a Tecnai G2 F 20 s-twin TEM at an accelerating voltage of 300 kV, respectively. Energy-dispersive X-ray spectroscopy (EDS) was performed to analyze the elemental composition. The scanning electron microscope (SEM) images were obtained using a Hitachi S-4800. X-ray photoelectron spectroscopy (XPS) analysis was conducted using a Thermo Scientific instrument and K-alpha surface analysis. The nitrogen adsorption–desorption isotherms were recorded using a Micromeritics ASAP 2420 surface area analyzer at liquid nitrogen temperature. Prior to gas adsorption, all photocatalysts were degassed for 3 h at 200 °C. The infrared (IR) spectra were recorded using an Avatar 370 Fourier transform infrared (FTIR) spectroscope. The spectra were acquired at a resolution of 4 cm2SO4 aqueous electrolyte. The as-synthesized samples supported on ITO substrate directly served as the working electrode, while a saturated calomel electrode (SCE) and a platinum wire were used as the reference and the counter electrodes, respectively. Cyclic voltammetry (CV) and galvanostatic charge−discharge (GCD) measurements were performed to examine the electrochemical performance of the working electrodes. Electrochemical impedance spectroscopy (EIS) was conducted by applying an alternating current voltage with a 0-mV amplitude in the frequency range of 0.01 Hz to 1 MHz. The specific capacities  of the Bi2S3 samples were estimated from the GCD curves based on the following equation:1 and t2 denote to the initial and terminational discharge time of the GCD curves, respectively.All the electrochemical measurements were performed using the electrochemical workstation (Biologic SP-200) using a three-electrode configuration in a 0.5 M Na2 gas for 20 min. The reaction was carried out using a 300 W Xe lamp (Max 303) with a light intensity of 50 mW cm−2. The amount of H2 gas generated during the reaction was monitored at one-hour intervals by collecting the gas samples in an airtight syringe. The analysis of the sample was carried out using a gas chromatograph (6500GC system-YL Instrument) equipped with a thermal conductivity (TC) detector and a molecular sieve 5A column with He as the carrier gas.Using the as-prepared photocatalysts, the photocatalytic hydrogen production was carried out by water splitting under simulated solar light irradiation. The reaction was carried out in a 150-mL tube-like quartz reactor with a round bottom. 5 mg of the photocatalyst was added to 50 mL of 5% aqueous lactic acid solution in a quartz reactor, which was then sealed with an air-tight rubber septum. The reactor was evacuated for 20 min, and the solution was purged with Nin-situ carbon coating also considerably simplifies the process and reduces the cost. Generally, D-glucose serving as a surfactant can generate carbon via a solid thermal decomposition reaction29. In the present synthesis methodology, we used ethanol as a solvent to disperse the Bi2S3 nanorods and D-glucose was introduced as the carbon source. When the D-glucose is subjected to the hydrothermal treatment at 190 °C, more than the glycosidation temperature, it tends to form C-C bonding that leads to the aromatization and carbonation. Initially, the glucose molecules undergo polymerization to form aromatic compounds or oligosaccharides. As the solution reach critical supersaturation, crosslinking between these macromolecules tends to the carbonization that results in a short single burst of nucleation. Here, the highly dispersed Bi2S3 nanorods, possessing highly reactive surface exposed outside, offers its surface to catalyze the carbonization of glucose (nucleation) that leads to in-situ deposition of carbon products around the Bi2S3 nanorods to produce carbonaceous shell. The growth of nuclei is subject to the reaction temperature, time and concentration. Herein, we studied the effect of reaction time , keeping the other two conditions constant, on the thickness of the carbon shell and discussed in the HRTEM section. Under the complex polymerization of D-glucose at hydrothermal conditions , Bi2S3 nanorod arrays employed as the templates form scalable core-shell C@ Bi2S3, where Bi2S3 nanorods are initially coated by carbonaceous nucleation on their outer surface. Under hydrothermal treatment, the D-glucose was degraded to carbon and anchored onto the surface of Bi2S3 nanorods13. As reported in the literature, the thickness of the carbonaceous layer typically depends upon the synthesis conditions30. For example, a glucose-derived carbon precursor can be readily integrated onto nanostructures in solution, which is carbothermally reduced to metallic ions by carbon with respect to hydrothermal temperature30. Saravanakumar et al.29 demonstrated dextrose as a carbon source for the synthesis of carbon-coated V2O5 nanorods. They demonstrated that the controlled hydrothermal treatment led the formation of rod-like carbon structures. In this work, the overall carbonization process is controlled based on the holding time to avoid the destruction of Bi2S3 nanorod arrays. It is well known that above 220 °C, sulfur is decomposed and oxides were formed. Therefore, we fixed the hydrothermal temperature at 190 °C and studied the effect of holding time on the carbonaceous layer formation.On the basis of the attempted experimental analysis, the formation mechanism of the core-shell structure and accompanying morphology evolution process is illustrated in Fig. 2S3 is observed in Fig. 2S3 nanorods with a lattice spacing of 0.36 nm that can be assigned to the (130) plane of orthorhombic Bi2S3, indicating that Bi2S3 nanorods favorably grew parallel direction to the (130) plane. The inset in Fig. 2S3, which is also consistent with the single crystalline Bi2S3 indexed as the (130) zone c-axis28.The morphological studies were performed using HRTEM and SEM. A representative HRTEM image of pristine Bi2S3 nanorods with respect to the holding time is examined via HRTEM. Figure 2S3 samples. The nanorods are fully enclosed by the carbon material, thus forming a core-shell structure. In the case of the C@Bi2S3 sample, a typical core-shell shape of organic/inorganic hybrid nanostructure is formed, with well-organized atomic structures of carbon layers on the surface of Bi2S3 nanorod. It can be inferred that the ultra-thin shell-like carbon layer is formed by the nucleation of carbonaceous molecules. Figure 2S3 and C@Bi2S3 at different holding times: 4, 6, 8, and 12 h. It is noteworthy that as the holding time is increased, the thickness of the carbon layer increases. Moreover, on the Bi2S3 nanorod surface, there is a ~2 nm thick coating layer, which is probably amorphous carbon resulting from the polymerization of glucose is seen for all the C@Bi2S3 samples. It was observed that the thickness of the carbon layer slightly increased with an increase in the holding time. However, the carbon layer becomes dense with increasing holding times which is due to the excess carbon particles deposited on the Bi2S3 nanorod. The HRTEM images depict a dense carbon layer on the Bi2S3 nanorods surface as highlighted by the yellow arrows. HR-TEM performed on the grown carbon layer on the Bi2S3 nanorods surface reveals its structural uniformity and amorphous nature. At different holding times, the Bi2S3 rods were assembled by the amorphous carbon particles with variable thickness and densities. In addition, the mesoporous features of the carbon layer attributed roughness to the surfaces of the Bi2S3 nanorods, leading to enhanced electrochemical properties. In other words, the homogeneous carbon layer structure could efficiently enhance the conductivity of the electrodes, limit the volume change of Bi2S3 materials, and keep the Bi2S3 electrode stable during oxidation–reduction reactions. Based on the HRTEM analysis, the C@Bi2S3 sample at an 8 h holding time is considered for further characterization and applications in this work.The decoration of the carbon layer on the surface of individual Bi2S3 sample. The SEM images indicate that the C@Bi2S3 structure comprises a large amount of homogeneous nanorods, which are covered by the amorphous carbon material. SEM observation indicates that the carbon was densely packed and uniformly covered the entire surface of Bi2S3 nanorods, resulting in the formation of core-shell structures. SEM images show that the nanorods have a length of approximately a few nanometers to submicron. Figure 2S3 and C@Bi2S3 samples. This result also confirmed the deposition of carbon materials throughout the Bi2S3 nanorods and provides evidence for the existence of carbon materials in the C@Bi2S3 sample. Furthermore, the HRTEM elemental mapping of the C@Bi2S3 sample is shown in Fig. 2S3 nanorod is also decorated with the carbon layer.Figure 2S3, which was well matched with JCPDS No. 89–8964. Interestingly, the weak peaks also match well with the standard pattern. In case of the C@Bi2S3 sample, similar diffraction peaks were observed owing to the amorphous nature of the carbon materials. As observed in the XRD result, the intensities of the diffraction peaks at 2θ = 11.08, 15.72, 17.56, 23.71, 24.92, 28.64, 31.11, 33.92, 35.91, 39.89, 42.69, 46.5, 48.44, 52.76, 62.71, 69.44, and 78.46 degrees corresponding to the (110), (020), (120), (101), (130), (230), (221), (410), (240), (141), (421), (431), (022), (312), (370), (561), and (670) planes of orthorhombic Bi2S3 respectively, agree well with reported values in literature28. Both the pristine Bi2S3 and C@Bi2S3 samples exhibit good crystallinity and all the peaks can be clearly attributed to the orthorhombic phase of Bi2S3. Carbon is not recognized in the pattern of the C@Bi2S3 sample, demonstrating the disordered nature of the carbon layer31. In fact, the carbon component in the as-prepared C@Bi2S3 sample is confirmed via SEM and HRTEM elemental mapping.The phase purity and structural features of the as-synthesized samples were verified via XRD, and the results are shown in Fig. 2S3 nanorods, Raman spectroscopy of pristine Bi2S3 and C@Bi2S3 samples was recorded. As shown in Fig. −1, which are well consistent with the reported literatures for the crystalline Bi2S332. From the partial enlarged drawing of C@Bi2S3 Raman spectra , the asprepared C@Bi2S3 possess higher BET surface area13. The Barrett−Joyner−Halenda (BJH) pore-size distribution curves  and galvanostatic charge/discharge tests, electron impedance, and photocurrent tests were performed. Figure 2S3 and C@Bi2S3 core-shell structures at a scanning rate of 10 mV s−1 for a potential ranging from −0.6 to 0 V (vs SCE) in a 0.5 M Na2SO4 electrolyte. As shown in Fig. 2S3 core-shell structure is larger than that of pristine Bi2S3, representing a greater specific capacitance. Figure 2S3 and C@Bi2S3 core-shell structures at various scanning rates. The voltammograms were recorded between −0.6 and 0 V at potential scan rates ranging from 1 to 250 mV s−1 in a 0.5 M Na2SO4 solution. No redox peak is observed at different scan rates in the CV curves, suggesting that the electrode is charged and discharged at a pseudo-constant rate over the complete voltammetric cycle. The CV curve at faster scan rates has a larger area with a greater charge capacitance compared with that at a lower scan rate.In order to estimate the electrochemical properties of the pristine Bi2S3 and C@Bi2S3 samples at a current density of 1 A g−1. During the charging and discharging steps, the charge curve of the samples were not symmetric to its corresponding discharge counterpart with a negligible internal resistance (IR) drop, indicating the supercapacitive phenomenon. The GCD curve of the C@Bi2S3 sample exhibits a longer discharging time compared with the charging time. This phenomenon is repeatedly observed in Bi2S3-based electrode systems36; however, the investigation of the exact mechanism of this phenomenon is still under progress. In addition, the GCD curves of the C@Bi2S3 sample at different current densities  is presented in Fig. Figure 2S3 and C@Bi2S3 electrodes. Both the samples demonstrated a semicircular arc at higher frequencies and a straight line at lower frequencies, indicating that the electrode processes are organized by the charge transfer  in the former region and by the diffusion of charges  in the absolute region. The intercept on the Z’ axis refers to Rs, including the solution resistance and the contact resistance, whereas the dimension of the semicircle reflects the electrode film resistance (Rf) and charge transfer resistance (Rct), which are consistent with reported literature13. EIS parameters, including the solution resistance (Rs), charge transfer resistance (Rct), and time constant (τ) were obtained as 1.2 Ω, 5.02 Ω, and 0.32 ms, respectively, for the C@Bi2S3 electrode, indicating fast charge/discharge processes, small solution resistance, and superior electrical conductivity at the electrode/electrolyte interface. Therefore, the carbon layer can efficiently bind with Bi2S3 nanorods, and thus improve electrical contact with the current collector13. This confirms that more active carbon participates in the charge/discharge reaction process, leading to a higher charge carrier mobility.The EIS analysis has been recognized as one of the principal methods to investigate the fundamental behavior of electrode materials, especially for supercapacitors. The impedance of both the samples are tested at frequencies varying between 0.1 Hz and 1 MHz at an open circuit potential with an AC perturbation of 0 mV. Figure −1 for pristine Bi2S3 electrode, while the specific capacitance of the C@Bi2S3 electrode is 333.43, 302.21, 280.16, 257.03, 243.97, 223.89, and 210.84 F g−1 at 1, 2, 3, 4, 5, 6, and 7 A g−1, respectively. The obtained value of the specific capacitance of the C@Bi2S3 electrode is higher than the previously reported values for carbon-decorated MoS2 (210 F g−1 at 1 A g−1)37. As the current density increased from 1 to 7 A g−1, the specific capacitance linearly decreased to 90.6 and 210.84 F g−1 with a 63.2% retention of its original value. These findings specify that both the electrodes have a remarkable rate capability.Figure 2S3 core-shell structure, consecutive GCD cycles were conducted at a constant current density of 4 A g−1. Figure 2S3 core-shell structure was examined using HRTEM, as shown in Fig. 2S3 still maintained even after suffering intense cycling test, which contributes to the remarkable cyclic stability. Moreover, the EIS of the 1st and 1000th cycle samples was conducted and compared. Figure 2S3 electrode before and after 1000 cycles. It can be seen that both the curves contained a vertical line parallel to the imaginary axis at a low frequency, signifying a pseudocapacitor behavior39. In addition, the Rct value was consistent before and after 1000 cycles (5.02 and 5.08 Ω), respectively, which is reliable with the remarkable stability, as confirmed by the cycling tests, suggesting the interconnected structure of core-shell features of C@Bi2S3.To explore the electrochemical stability and durability of the C@Bi2 production over the pristine Bi2S3 and C@Bi2S3 samples via water splitting using a 5 vol% lactic acid solution as a sacrificial agent. Due to the low bandgap, the recombination of electrons and holes in the Bi2S3 semiconductor is rapid leading to lower quantum yields. Here the carbon shell on the Bi2S3 prevents the recombination process by accepting an electron from the conduction band of Bi2S3. Also the high conductivity of carbon shell affluences the transportation of electrons to the reaction center that is the surface of carbon shell where the proton reduction process occurs. It is obvious that the photocatalytic H2 generation increases with an increase in the irradiation time. Interestingly, the amount of H2 generation is higher over the core-shell structure of C@Bi2S3 (754.34 µmol h−1 g−1) compared to the pristine Bi2S3 (408.54 µmol h−1 g−1), which is a 1.84-fold improvement in H2 production over the core-shell structure of C@Bi2S3. It is believed that the improved photocatalytic activity may be associated with the core-shell feature of C@Bi2S3, which leads to close contact between the organic/inorganic frame networks. This core-shell interconnected assembled structure could also transport photo-induced electrons and holes to the binding sites; thus, the efficient oxidation of water occurred in the presence of lactic acid as a sacrificial agent, which is also consistent with previously reported literatures42. In addition, the core-shell heterostructure may facilitate remarkable electron transfer compared with the pristine one, which can efficiently improve hydrogen production43. As it already discussed in Fig. 2S3 sample showed lower semicircle as compared to the pristine Bi2S3. The lower arc for the C@Bi2S3 sample is resulted from the less resistance of the material for the charge transfer process which is crucial for the electron transfer to the protons during the water splitting reaction to produce hydrogen. Thus, the presence of carbon shell improves the charge transfer characteristics of Bi2S3 that might be the reason for enhanced activity.Figure 2S3 catalysts prepared at various reaction times . All the C@Bi2S3 photocatalysts showed superior H2 production than the pristine Bi2S3. This infers that the presence of carbon shell has strong influence on the enhanced photocatalytic activity of Bi2S3. Maximum H2 production was observed over the C@Bi2S3–8h catalyst which was prepared at 8 h of reaction time. However, the C@Bi2S3−12h sample prepared at 12 h reaction time showed slightly lower photocatalytic activity than the C@Bi2S3−8h sample. The excess reaction time might have resulted in the formation of overgrown thick carbon shell over the Bi2S3 in which the photoexcited electron in the Bi2S3 core has to travel longer path to reach the surface of the carbon shell where the proton reduction takes place. This results in the recombination of excited electrons with the holes and subsequent reduction in the photocatalytic activity. Also the excess reaction time might have formed individual carbon particles which may not be in direct contact with the C@Bi2S3 core shell structure. In the present study, the C@Bi2S3 core shell material prepared at 8 h reaction time has shown the optimum photocatalytic activity and hence we believe that 8 h reaction time is ideal for the growth of carbon shell on the surface of Bi2S3 core. Thus the C@Bi2S3−8h catalyst was selected for further studies.The effect of carbon shell thickness on the photocatalytic activity for the hydrogen production has been studied over C@Bi2S3 and C@Bi2S3 catalysts are conducted as shown in the Fig. 2 for every five hours the activity of the catalyst is retained. In order to optimize the lactic acid concentration, reactions were carried out over pristine Bi2S3 and C@Bi2S3 catalysts using lactic acid: water mixtures with different lactic acid amounts. The results are summarized in Fig. 2. The photocatalytic hydrogen rate increases with the increase of initial lactic acid concentration. The optimal concentration of lactic acid is at 5% with a photocatalytic hydrogen rate of 408.54 and 754.34 µmol h−1 g−1 over the pristine Bi2S3 and C@Bi2S3 catalysts, respectively. And with increase in lactic acid concentration over 5%, no increase is seen in H2 production. The reason may be that at higher concentrations the surface of the photocatalyst extents saturation with no further improve in H2 production.Time on stream activity over the pristine Bi2S3 core-shell structures are more stable and reusable visible light–driven photocatalysts, which represent a fruitful methodology for harvesting solar energy for H2 evolution and supercapacitor applications.For practical applications, the reusability and stability of as-prepared photocatalysts is a key parameter. Figure 2S3 and C@Bi2S3 samples. The charge carrier separation phenomena of these samples were tested via on/off photocurrent at a bias voltage of 0.4 mV under simulated solar light irradiation, as shown in Fig. 2S3 core-shell structure exhibits a remarkably higher photocurrent compared to the pristine Bi2S3, which is consistent with the above electrochemical performance  improved visible light absorption property helps in producing more electrons and holes, which advances photocatalytic activity, (ii) the remarkable specific surface area of the C@Bi2S3 core-shell structure provide more reactive sites for promoting hydrogen evolution, (iii) skillfully designed heterostructures prominently endorse the separation of electrons and holes, and (iv) the excellent properties of carbon materials such as high conductivity and more active sites benefit charge carrier separation and charge transfer to diminish the electron–hole pair recombination and enhance the photocatalytic hydrogen evolution rate. Finally, the introduction of carbon can reduce the H+ reduction overpotential and act as a catalytic active site.Based on the above results and discussion, a plausible mechanism of photocatalytic performance can be described as shown in Fig. 2S3 nanorods. The as-fabricated core-shell heterostructure can be directly employed as an electrode for supercapacitors, demonstrating a remarkable specific capacity of 333.43 F g−1 at a current density of 1 A g−1 and a considerable cycling stability with a capacity retention of 97.36% after 1000 cycles at a current density of 4 A g−1. The remarkable cycling performance, combined with robust rate capability, exhibit the potential of C@Bi2S3 to be used as a novel electrode material for a supercapacitor. In addition, the core-shell structure of the C@Bi2S3 electrode demonstrated a H2 evolution rate of 754.34 µmol h−1 g−1, a 1.84-fold improvement over the pristine Bi2S3. This outstanding improvement was due to enhanced specific surface area with site edges of carbon that helps in the effective separation and transportation of photoinduced carriers. It is expected that the proposed synthetic strategy has potential for the exploration of advanced electrochemical cell materials.We attempted and demonstrated a promising core-shell design of C@BiSupplementary Information


The characteristic personality traits of ADHD patients were the high level of impulsiveness associated with lower values of agreeableness. All participants performed a probability gambling task (PGT) with two frequencies of the feedback information of the outcome. For each trial, ERPs were triggered by the self-paced trial onset and by the gamble selection. After trial onset, N2-P3a ERP component associated with the attentional load peaked earlier in the ADHD group than in controls. An N500 component related to the feedback frequency condition after trial onset and an N400-like component after gamble selection suggest a large affective stake of the decision making and an emphasized post-decisional evaluation of the choice made by the ADHD participants. By combining ERPs, related to the emotions associated with the feedback frequency condition, and behavioral analyses during completion of PGT, this study provides new findings on the neural dynamics that differentiate controls and young ADHD adults. In the patients' group, we raise the hypothesis that the activity of frontocentral and centroparietal neural circuits drive the decision-making processes dictated by an impaired cognitive workload followed by the build-up of large emotional feelings generated by the conflict toward the outcome of the gambling choice. Our results can be used for new investigations aimed at studying the fine spatiotemporal distribution of cortical activity, and the neural circuits that underly the generation of that activity, associated with the behavioral deficits characteristic of ADHD.Attention-deficit hyperactivity disorder (ADHD) is characterized by deficits in executive functions and decision making during childhood and adolescence. Contradictory results exist whether altered event-related potentials (ERPs) in adults are associated with the tendency of ADHD patients toward risky behavior. Clinically diagnosed ADHD patients ( Decision making is an essential phase in a volitional act, that follows problem analysis, deliberation and evokes execution. The processes involved in the cognitive control of action and thought operations are divided into two modes according to the model developed by Norman and Shallice : (i) potImpaired decision making is among the characteristic symptoms of patients affected by Attention Deficit/Hyperactivity Disorder (ADHD). This behavioral disorder of childhood and adolescence is characterized by primary deficits of executive functions and clinical symptoms including excessive inattention, hyperactivity and impulsiveness that persist into adulthood in a vast proportion of the diagnosed adolescents Barkley, . Adults Brain activity triggered in time by a repeating physical or mental stimulus recorded using electroencephalographic techniques and averaged over many repetitions of the same stimulus constitutes the basis of the event-related potentials (ERPs)  and the high frequency (HF) conditions for each group of participants at each recording site. Our hypothesis is that young ADHD patients are characterized by abnormal dynamics while performing decision-making tasks and that specific ERP components characterize those patients. We suppose that difference between ADHD and controls appear at first in frontal areas when the cognitive load is associated with the stimulus contextual value, then followed by the build-up of an emotional response associated with the difficulty to evaluate the outcome of decision making. To test this hypothesis, we recorded behavioral and ERP data in a sample of young adults affected by ADHD during completion of a Probabilistic Gambling Task (PGT), where the participants had to choose the portion of a preassigned amount they had to gamble in a game. We have manipulated the frequency of the feedback information aiming to assess the ERP components associated with the anticipatory processing of the target stimulus, attentional priming, cognitive workload, and response selection and reprogramming.p = 0.05, unless otherwise reported. For parametric comparisons of distributions, we used Student's t-test and Cohen's d effect size. For Chi-square tests, the effect size is reported by Φ for 2 x 2 contingency tables, otherwise by Cramer's V  = 0.265, p = 0.61] nor for ASRS .Two weeks prior the experimental session, all potential participants were requested to fill the Conners' Adult ADHD Rating Scales-Self Report   model of personality   and gambling choice (trigger event I), delimited a time interval, the termination of which corresponds to a voluntary action, i.e., the choice of a selected amount to gamble. The outcome of the gambling was either to win four times the selected value, with a probability Pwin = 1/3, or to loose the entire amount with a probability Ploose = 2/3 with a uniformly distributed probability  in case of loss, or 44 = (20−8) + (8 × 4) in case of win). For each trial in the “high-frequency feedback” condition (HF) the participant was informed, 4 s after the choice, about the amount of points held after gambling. In the “low-frequency feedback” condition (LF) the participant was just informed that the outcome of the gambling was determined. In both conditions  the overall amount of points held by the participant was displayed every four trials. Each participant played the PGT in 10 alternated blocks of HF and LF 16 trials each, hence 80 trials for each condition.The PGT is a modified version of the original Gneezy-Potters' task , by a risk index (RI) and by response times (RT). In particular, we considered the total gains earned during low-frequency feedback trials (TG(LF)), and during high-frequency feedback trials (TG(HF)). The relative number of trials a participant gambled 0, 4, or 8 points defined a low-risk index LR. A high-risk index HR was defined as gambling amounts of 12, 16, or 20 points. A risk index RI centralized within the range  was calculated as RI = (HR−LR)/(HR+LR). Then, an RI toward −1 is characteristic of a risk-averse strategy, an index toward +1 for a risk-seeking participant, and RI ≈ 0 being associated with a risk-neutral attitude. Each participant could be further characterized with the corresponding RIs calculated following the feedback frequency, i.e., RI(LF) and RI(HF). The behavior of the participants was also assessed by measuring the response times (RT) in ms. The trials with RT < 250 ms and RT > 10 s were discarded. Additional trials detected as outliers on the basis of a robust analysis , mounted on a headcap  and referenced to the linked earlobes. The analysis has been focused on electrode sites POz, Pz, CPz, Cz, FCz, and Fz. This study is not aimed at performing source localization and we do not define regions of interest (ROIs) following the classical definition. Vertical and horizontal ocular movements were recorded using two pairs of bipolar electrodes placed beneath and above each eye next to the lateral canthi. The data acquisition  was set with a sampling rate of 1,024 Hz at 24 bits resolution and band-passed filtered with a lower cutoff at 0.05 Hz and an upper cut-off at 200 Hz. Electrode impedances were checked and kept always below 20S) and by clicking on the selected investment to gamble (the event I), as illustrated in Figure S and I). Visual inspection of the EEG was performed to remove immediately those epochs containing high amplitude muscle activity related noise, large eye blinks, and other easily identifiable artifacts. Infomax Independent Component Analysis was used to correct saccade-related eye movements whenever possible or to reject the epoch  between controls  and ADHD . ERP analyses were performed on the artifact-free trials, band-pass filtered between 0.1 and 30 Hz (−12dB/octave). Subsequently, the trials were baseline corrected to the interval 500 ms prior to trigger onset and averaged for both conditions LF and HF. After removing all artifacts, the number of usable epochs for any particular ERP analysis had to be more than twenty.The brain signals were preprocessed and analyzed with BrainVision Analyzer 2.0.4 . Markers were used off-line to segment the continuous EEG data into epochs triggered by pressing the spacebar  and one between-subject factor (groups: controls and ADHD) revealed a significant interaction between the factors for openness , conscientiousness , extraversion  and emotionality . In ADHD patients, we observed significant lower scores for conscientiousness, extraversion, and agreeableness (Table t(16) = 2.61, p = 0.02, d = 0.10, Table HEXACO scores within each dimension of personality were determined for each subject and robust correlations were computed for each group Table . The robTotG gained by the ADHD was not different from controls  = 0.481, p = 0.49). However, a refined factorial analysis showed a very significant interaction between the group factor and the CAARS index on TotG . The CAARS index was positively correlated in ADHD, and negatively correlated in controls, with the cumulated amount of points gained during both conditions  = 1.400, p = 0.24]). The response times of ADHD were slower than controls. In addition, the ADHD group was characterized by faster response times during LF than during HF trials  = 0.823, p = 0.37] nor during HF trials .The overall amount of points ls Table . The robs Figure . The pars Figure . No gendM) appeared about 150 ms before pressing the spacebar (the trigger event S)  at approximately 175 and 250 ms. Immediately following P3a there was a second positive component (P3b), usually associated with a cognitive workload, at a latency near 340 ms. During the time interval between the events S and I, we observed a slow negative deflection after P3b, with greater amplitude toward the parietal areas. This component is usually referred to as CNV (contingent negative variation) and is not further analyzed in this study  and within-subject factor (conditions: HF and LF) on the latencies of ERP components recorded at the frontocentral  and centroparietal  sites were studied by robust statistics  when the participant elaborates the gambling strategy. For main effects, we considered a linear mixed-effects model of the latency of an ERP component depending on two within-subject factors  and one between-subject factor (groups: controls and ADHD). This model assumes that the latency of an ERP component is related to fixed effects, i.e., the interaction between the groups, recording sites, and conditions factors, and to additional independent random effects for each within-subject factor. In both groups, the analysis by the linear mixed-effects model revealed a significant effect of frequency feedback on P3a latency at frontocentral and centroparietal locations . This effect might suggest that this ERP component is generated by a neural circuit associated with processing the frequency feedback outcome.Simple effects of between-subject factor . The peak of P3a tended also to occur later in the ADHD than controls . On the opposite, notice that P3b peaked earlier in ADHD than controls , in particular during the HF condition  along the frontocentral sites . Those studies reported ADHD patients characterized by low scores of conscientiousness and agreeableness and a high score of neuroticism  reported in adult ADHD patients (Thoma et al., Event Related Potentials elicited by a PGT are valuable markers of decision-making deficits related to ADHD, more sensitive than classical behavioral markers based on the total gain, gambling amount, and risk-taking indexes. We used two conditions characterized by a low and high frequency of feedback information of the outcome. The manipulation of outcomes' feedback frequency showed that at trial onset the N2-P3a components, associated with expectation-association-orienting processing, peaked earlier in ADHD than in controls. Our results extend previous evidence in ADHD children and adolescents that deficits in the executive attention network, responsible for error processing and conflict monitoring, and the dissociation between perceptual and response conflicts, selectively modify the neural dynamics involved in decision-making processes.Authors SM, AL, and AV contributed equally to all stages of this work. MB contributed the psychiatric assessment and screening of the participants. LG contributed to the experimental design of the behavioral task.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Exposure to pollutants during pregnancy has been related to adverse birth outcomes. LBW can give rise to lifelong impairments. Prematurity is the leading cause of LBW, yet few studies have attempted to analyse how environmental factors can influence LBW in infants who are not premature. This study therefore sought to analyse the influence of air pollution, noise levels and temperature on LBW in non-premature births in Madrid during the period 2001–2009.2.5, NO2 and O3 concentrations, noise levels, and temperatures on LBW among non-premature infants across the period 2001–2009. Our analysis extended to infants having birth weights of 1,500 g to 2,500 g (VLBW) and less than 1,500 g (ELBW). Environmental variables were lagged until 37 weeks with respect to the date of birth, and cross-correlation functions were used to identify explaining lags. Results were quantified using Poisson regression models.Ecological time-series study to assess the impact of PM2.5 was the only pollutant to show an association with the three variables of LBW in non-premature births. This association occurred at around the third month of gestation for LBW and VLBW (LBW: lag 23 and VLBW: lag 25), and at around the eighth month of gestation for ELBW (lag 6). Leqd was linked to LBW at lag zero. The RR of PM2.5 on LBW was 1.01 (1.00 1.03). The RR of Leqd on LBW was 1.09 (0.99 1.19)(p<0.1).Across the study period 298,705 births were registered in Madrid, 3,290 of which had LBW; of this latter total, 1,492 were non-premature. PM2.5 had influence on LBW. The adoption of measures aimed at reducing the number of vehicles would serve to lower pregnant women's exposure. In the case of noise should be limited the exposure to high levels during the final weeks of pregnancy.The results obtained indicate that PM In recent years, various studies have linked exposure during pregnancy to chemical environmental pollutants present in the urban atmosphere to a number of adverse birth outcomes –4, inclu2.5, PM10 and NO2 [2.5 and ultrafine particles appear to be those which contribute most, linked to a joint action between oxidative stress and pro-inflammatory state. Oxidative stress can be triggered by direct formation of reactive oxygen species coming into contact with free radicals in blood, either because PM2.5 is transporting soluble transition metals [2.5), have a high oxidative capacity per se and can enter the cell and affect the mitochondria [2 concentrations on adverse birth outcomes and LBW [As described in detail previously  a growin and NO2 ,23,24. In metals , or becachondria . Pregnanchondria . Althoug and LBW ,15,28–31Furthermore, recent studies indicate that it is not only traditional chemical pollutants present in an urban atmosphere which can influence these adverse birth outcomes, but that other environmental variables, such as traffic noise ,17,18,32As described previously  in relatAccordingly, the aim of this study was to use a time-series design to analyse the influence of chemical air pollution, noise levels and temperature on LBW among non-premature infants in the city of Madrid, identifying -where possible- the most susceptible periods of exposure during pregnancy by means of significant explanatory lags. The relevance of the results obtained lies in the fact that exposure to these environmental variables can be modified, both at a governmental level by adopting measures targeted at reducing the levels of the environmental risk factors analysed, and at the level of the pregnant women themselves by limiting their personal exposure.The city of Madrid is a densely populated metropolitan area situated in the central region of Spain. During the study period, 2001–2009, it had a mean population of 3,164,245 and a birth rate per 1000 population of 10.5, slightly higher than the national rate of 9.1 . The stu3) of air pollutants, particulate matter less than 2.5 and 10 μm in diameter (PM2.5 and PM10), tropospheric ozone (O3) and nitrogen dioxide (NO2), were supplied by the Madrid Municipal Air Quality Monitoring Grid. All measurements were made using the gravimetric method or an equivalent method (beta-attenuation). This network consists of 27 urban background stations across the city. Measurements of acoustic noise pollution were Leqd, equivalent diurnal noise level (7–23 hours) in dB(A), and Leqn, equivalent nocturnal noise level (23–7 hours) in dB(A).A time-series analysis was performed to assess the short-term impact of the following environmental variables. Daily mean concentrations  in Madrid were furnished by the State Meteorological Agency (AEMET).These daily values were grouped into mean weekly values for respective variables. Lastly, we controlled for linear trend, seasonality and the autoregressive nature of the series itself.2.5, PM10, O3 and NO2) and noise levels (Leqd and Leqn) were introduced into the model as linear components without threshold.However, the relationship between ambient maximum temperature and neonatal outcomes displayed the usual V-shaped pattern already observed in the case of mortality and morbidity variables [We decided to fit autoregressive, over-dispersed Poisson regression models of the neonatal outcome variables . Due to their linear relationship, the air pollutants  among the residuals of the prewhitened series, with prewhitening being performed using Box-Jenkins methodology . This mep<0.05), the results of the final models were expressed as relative risks (RRs) and their 95% confidence intervals. These RRs were shown for each 10 μg/m3increase in the case of the chemical air pollutants, each 1 dB (A) increase in the case of noise levels, and each 1°C increase/decrease in the case of temperature. Based on the respective RR, we then calculated the attributable risk (AR) associated with this increase, by means of the following equation: In the case of statistically significant variables , as can be seen from The mean number of weekly births with low weight was 3.0, which meant that 42.9% of births with low weight were not premature and 57.1% were premature.2.5 concentrations were exceeded on 329 days (10.0%) and daily PM10 concentrations were exceeded on 446 days (13.6%) across the study period. In 2.5 concentrations in Madrid 2004–2009, can be observed. The WHO guideline values for NO2 and ozone (O3) were not comparable measurements with the measurements in our study.The WHO guideline values  for dailInsofar as noise levels were concerned, the mean Leqd value was 64.6 dB(A) with a daily maximum of 69.0 dB(A), and the mean Leqn value was 59.4 dB(A) with a daily maximum of 67.2 dB(A): the WHO guideline values  were excp<0.05) between the different series of independent environmental variables and the variables corresponding to low weight in non-premature births. It should be noted that PM2.5 was the sole chemical pollutant to be related to the three selected variables of LBW among non-premature births. These associations occurred: in LBW and VLBW, at around 24 weeks before birth (LBW: lag 23 and VLBW: lag 25), namely, in the third month of pregnancy; and in ELBW, at 6 weeks before birth, namely, around the eighth month of pregnancy. In the case of traffic noise levels, mean diurnal noise level, Leqd, was the only variable to show an association with LBW, and this effect occurred at lag zero, i.e., during the birth week itself.In terms of temperature, there were heat waves on 216 days (6.6%) and cold waves on 34 days (1.0%) over the study period. 2.5 on the three variables related to low weight displayed very similar ARs, of around 2%. Leqd, however, displayed an appreciably higher AR than that of PM, i.e., around 8%, though this was exclusively for the variable, LBW, and this increase in risk was significant at only p<0.1.Spain has one of the highest LBW percentages in Europe, after Greece, Portugal and the Czech Republic . With re2 values set by the European Directive [2.5 emission values. The reason for this is that EU PM2.5 concentrations refer to mean annual values and do thus not come into operation for the purpose of triggering immediate intervention measures, as in the case of NO2 [2.5 concentrations that show the most impact on the population, children and persons over the age of 75 years [2.5 is the environmental chemical pollutant which displays a statistically significant association with the three indicators of low weight analysed in this study is not in contradiction with other studies in which NO2 has been associated with adverse birth variables [2, there are many papers that link PM2.5 to adverse birth variables [2.5 on adverse birth variables is similar to [2 [2.5 and not NO2, something that corroborates our results, since, has already been pointed out, prematurity is the principal cause of low weight. In the few time-series studies on adverse birth outcomes in which PM and NO2 were individually introduced, short-term associations were observed with PM, rather than with NO2 [Despite the fact that pollution prevention plans in Madrid are activated by exceedance of hourly NOirective , this doe of NO2 . Nonethe75 years –53. The ariables ,11,12. Fariables ,22,24. Ear to [2 . With rewith NO2 –18.2.5 concentrations and both LBW and VLBW is established 23 to 25 weeks before birth, namely, in the third month of pregnancy. This result is in line with those obtained by Arroyo et al. [2.5 and PTB is established in the first and third months of pregnancy. Its small size and anthropic composition mean that, on being inhaled and reaching the blood circulation, PM2.5 particulate matter can cause oxidative stress [2.5 was related to ELBW in the eighth month of pregnancy (lag 6). These results are in line with the study conducted in Beijing [2.5 concentrations in the eighth month of pregnancy translates as higher birth weight. Studies conducted on individual exposures to air pollutants in the different trimesters [2.5. Maternal factors associated with poorer foetal growth include maternal hypertension and cardiopulmonary disease [The association between PMo et al.  for Madro et al.  indicatee stress ,55, a pre stress  and pro-e stress  with ense stress , this wie stress . Further Beijing  which shimesters  have shoimesters  in relat disease , though  disease –64.2.5 [Evaluation of the results obtained for the factor of noise exposure shows that noise was the single environmental pollutant that most often exceeded WHO guideline values, both diurnal and nocturnal, across the study period. Recent morbidity-mortality studies in Madrid –67 have 2.5 , and tha2.5 ,18. The 2.5 ,17,18. L2.5 , noise cWith respect to the variable "temperature", the number of heat and cold waves which occurred in Madrid across the study period (216 and 34 respectively) and their effects on population health , includi2.5 concentrations or dB(A), as has been done by other studies [3/m3 in PM2.5 or of 1 dB(A) in Leqd and another who is not so exposed. The 2% increase in risk of LBW for every 10μg/m3increase in PM2.5 was of the same order as that reported by similar studies [2.5, as was also the case in premature births in Madrid [The nature of our longitudinal study renders it impossible to quantify to what precise degree low weight is associated with an increase in PM studies ,60. What studies ,24. Oncen Madrid  and evenn Madrid .With respect to the limitations of this study, an ecological study such as ours suffers from the ecological fallacy. Furthermore, an acknowledged limitation of all studies of environmental data as it is previously described in  is that 2.5) had an important influence on LBW in Madrid. In such an urban atmosphere, the source of PM2.5 is linked to the number of diesel vehicles. Hence, the adoption of measures at a governmental level to reduce the number of these vehicles would result in a lower exposure of pregnant women to this pollutant and, by extension, in a possible decrease in the number of infants with LBW. In the case of noise, 80% of which is traffic-generated in a city such as Madrid [The results obtained in this study indicate that during the study period, chemical pollution Click here for additional data file.


DRD4) is implicated in the etiology of attention-deficit/ hyperactivity disorder (ADHD). In particular, ADHD in European-ancestry population is associated with an increased prevalence of the 7-repeat (7R) allele of the exon 3 VNTR. However, it is intriguing to note that the 7R allele has been found to be of very low prevalence in the Chinese general population. In a previous case-control study, our research team had found that the 7R allele was similarly absent in Chinese ADHD children in Hong Kong. Instead, there was an increased prevalence of the 2R allele in Chinese ADHD children. Interestingly, in Asian samples, the 2R allele had been found to be an evolutionary derivative of the 7R allele with equivalent biochemical functionality. So, the finding of an association between ADHD and 2R allele in Chinese population does not exactly contradict the original 7R allele finding in European-ancestry population. However, given the potential pitfall of population stratification in the previous case-control design, this current study tested the 2R allele and ADHD association using a methodologically more rigorous family-based approach on 33 Chinese ADHD probands who had favorable clinical responses to stimulant medication (methylphenidate). Haplotype Relative Risk (HRR) analysis and Transmission Disequilibrium Test (TDT) both showed a significant preferential transmission of the 2R allele from the biological parents to ADHD probands . A second hypothesis speculates that it is the deviation, including 7R and 2R alleles, from the conserved ancestral 4R allele which confers risk to ADHD. Thus, a preferential transmission of non-4R alleles, against the 4R allele, from biological parents to their ADHD probands is predicted. Both HRR analysis and TDT confirmed such prediction . This study re-confirmed the original finding of a previous study that in Chinese population, the 2R allele of the DRD4 exon 3 VNTR was related to ADHD. This endorses the general thesis that DRD4 exon 3 VNTR polymorphism is related to ADHD, despite that the exact length or number of repeats of the associated alleles varies across ethnicity. This in turn supports the dopamine dysregulation theory of ADHD.The 48-basepair (48-bp) variable number tandem repeat (VNTR) polymorphism in exon 3 of the dopamine receptor D4 gene ( Attention-deficit/hyperactivity disorder (ADHD), a neuropsychiatric disorder, is characterized by age-inappropriate inattention, hyperactivity and impulsivity, with male to female ratio ranging from 3:1 to 9:1 . PreviouDespite the high estimated heritability of ADHD, genome-wide association studies (GWAS) have so far failed to detect any consistent polymorphism related to ADHD at the genome-wide significant level –12. ExpeInstead, the traditional candidate gene approach, which is theory-driven and requires much smaller sample sizes to achieve adequate statistical power, has proposed genes associated with ADHD, based upon the dopamine (DA) dysregulation theory . The stiDRD4) is the most extensively investigated with three quarters of its studies producing consistently positive results [DRD4 carries a polymorphism, which is a 48-basepair (48-bp) variable number tandem repeat (VNTR) and is located at the exon 3 of the gene. The alleles of this polymorphism range from 2 to 11 repeats with the 4-repeat (4R) allele being the most prevalent [DRD4 exon 3 7R allele published in 1996 [Among the dopamine system genes, dopamine receptor D4 gene  [DRD4 exon 3 VNTR alleles.The population prevalence of the  Chinese . A serie Chinese –33. So, alleles) . Table 1DRD4 exon 3 alleles and their linkage disequilibrium with adjacent polymorphisms were examined, the haplotypes of the particular 2R allele in Asians were found to originate from recombination between a 4R allele and a 7R allele [Interestingly, one study by Wang et al. found that when the sequences of the individual motifs of R allele . The D4 R allele . Thus, tR allele . UnfortuDRD4 exon 3 VNTR polymorphism, particularly the 2R allele, in Chinese ADHD children and to overcome the limitation of population stratification of the previous case-control study by Leung et al. [To further clarify the role of g et al. , a familg et al. ,36. Any g et al. ,37. It iThirty-three Chinese ADHD probands, aged between 6 to 15 years , and their biological fathers and mothers participated in this study. They were recruited from child psychiatric clinics in Hong Kong. Due to the gender ratio of ADHD children in local child psychiatry clinics being around 10  to 1 , only boys were recruited for the present study. This was because a mere few ADHD girls among a majority of boys would complicate the analysis and interpretation of the results.th Edition (DSM-IV). This was then followed by a structured diagnostic interview using the Parent-informant version of Diagnostic Interview Schedule of Children-4th Edition (P-DISC-4) for a broad range of childhood psychiatric disorders, including ADHD [ADHD was first diagnosed by experienced child psychiatrists according to the Diagnostic and Statistical Manual of Mental Disorders– 4ing ADHD . The cliDRD4 exon 3 VNTR polymorphism were performed according to a previously described method [Venous blood was taken from each ADHD boy and his two biological parents. DNA extraction and genotyping of the d method ,39. For The Haplotype Relative Risk (HRR) analysis  and TranDRD4 exon 3 VNTR allele frequencies of the ADHD probands and their two biological parents are shown in 2  = 3.15, pone-tailed = 0.038,)  = 2.78, pone-tailed = 0.048, OR = 2.29)  = 2.04  . TDT fur = 2.29) .2  = 3.59, pone-tailed = 0.029, OR = 2.07; McNemar’s χ2  = 3.38, pone-tailed = 0.032, OR = 2.43, respectively). In the former analysis, 63% of the non-4R alleles, compared to 45% of the 4R allele, was preferentially transmitted from the parents to the ADHD children, while in the latter, 24 informative parental meioses were identified, in which 17 non-4R alleles (71%) were transmitted, compared to 7 (29%) that were not transmitted.Our second hypothesis predicted a preferential transmission of non-4R alleles, against the 4R allele, from biological parents to their ADHD probands. Tables DRD4 exon 3 VNTR had been found to be of increased prevalence in Chinese ADHD children [In a previous case-control study, the 2R allele of the children . UnfortuDRD4.This finding of an association between ADHD and the 2R allele is superficially in discrepancy with findings from European-ancestry ADHD samples, which indicate an association with the 7R allele instead. However, the 2R allele may be as noteworthy as the 7R allele in its association with ADHD due to the evolutionary connection between the two alleles in Asians and their similar biochemical functionality. Therefore, our current finding of an association between ADHD and the 2R allele, based on a methodologically more rigorous family-based design, reinforces that of the earlier case-control study  and addiCompared to the modest effect sizes of the 7R allele in ADHD with ORs of 1.27–1.34 estimated from meta-analysis of both case-control and family-based studies ,26, or wDRD4 exon 3 VNTR individual alleles Click here for additional data file.


ADHD) and autism spectrum disorder (ASD) show significant behavioural and genetic overlap. Both ADHD and ASD are characterised by poor performance on a range of cognitive tasks. In particular, increased response time variability (RTV) is a promising indicator of risk for both ADHD and ASD. However, it is not clear whether different indices of RTV and changes to RTV according to task conditions are able to discriminate between the two disorders.Attention deficit hyperactivity disorder (ASD (n = 19), ADHD (n = 18), ASD + ADHD (n = 29) and typically developing controls  performed a four‐choice RT task with slow‐baseline and fast‐incentive conditions. Performance was characterised by mean RT (MRT), standard deviation of RT (SD‐RT), coefficient of variation (CV) and ex‐Gaussian distribution measures of Mu, Sigma and Tau.Children with ADHD‐only and ASD + ADHD demonstrated increased MRT, SD‐RT, CV and Tau compared to TDC and ASD‐only. Importantly, greater improvement in MRT, SD‐RT and Tau was demonstrated in ADHD and ASD + ADHD from slow‐baseline to fast‐incentive conditions compared to TDC and ASD‐only.In the slow‐baseline condition, categorical diagnoses and trait measures converged to indicate that children with ADHD compared to children with ASD. These findings suggest that RTV can be distinguished in ASD, ADHD and ASD + ADHD based on the indices of variability used and the conditions in which they are elicited. Further work identifying neural processes underlying increased RTV is warranted, in order to elucidate disorder‐specific and disorder‐convergent aetiological pathways.Slower and more variable RTs are markers of ADHD compared to ASD and typically developing controls during slow and less rewarding conditions. Energetic factors and rewards improve task performance to a greater extent in children with  Attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are common and highly heritable childhood‐onset disorders. Although ASD and ADHD are separate diagnoses, they share some behavioural and genetic features , as indexed by RTV, has been shown in both ASD and ADHD  took part in the study. The age range was 8–13 years; there was no significant difference in age across groups  and then underwent systematic and rigorous clinical assessment to confirm pure or comorbid research diagnosis  condition consecutively for three trials. The smiley faces appeared below the circles in the middle of the screen and were updated continuously. The fast‐incentive condition was always administered after the baseline condition and, as such, does not involve a similar learning phase. The children earned small prizes (vouchers) after completion of the fast‐incentive condition.Performance measures in the Fast task included errors of omission (failure to respond to the target) and commission (incorrect responses), reaction time to target stimuli , within‐subject variability in reaction times (SD‐RT) and the coefficient of variation , calculated across correct responses that were detected between 200 and 1,500 ms poststimulus, excluding anticipations or excessively slow responses. RT data were also characterised using a mixture of the Gaussian and exponential distributions, called the ex‐Gaussian distribution Luce, . Mu and One participant (one ASD + ADHD) was excluded from analysis due to extreme omission errors (<30% nonresponse to target in baseline condition), indicating lack of attention to task. In the slow‐baseline condition, MRT, Mu and Sigma were nonnormally distributed; in the fast‐incentive condition, MRT, SD‐RT, CV, Mu, Sigma and Tau were nonnormally distributed; and for difference scores calculated between conditions, MRT and CV were nonnormally distributed (indicated by sktest in Stata). Each of these parameters was therefore log‐transformed. The pattern of findings was retained for transformed and nontransformed data.p‐values. A series of repeated‐measures ANOVAs were used to examine change in task performance from the slow‐baseline to the fast‐incentive condition. The task parameters investigated in the repeated‐measures analyses are limited to those that showed group differences in the slow‐baseline condition.Groups were compared on performance in the slow‐baseline condition using multivariate ANOVA with group as the between‐subjects factor. Multiple comparisons were corrected using Sidak‐adjusted p < .05 (two‐tailed) and trends (p < .10) were followed up with post hoc tests. Sidak correction was used to correct for multiple testing. Effect sizes (Cohen's d) were calculated using the difference in the means, divided by the pooled standard deviation of the data.Age was a significant covariate for all parameters and was therefore retained in the analyses. The pattern of results was retained when IQ was entered as a covariate (see Supporting Information). The group analyses were performed in two stages: a comparison of four groups of TD, ASD, ADHD and ASD + ADHD to assess differences between pure and comorbid clinical groups; and 2 × 2 comparisons with ASD diagnostic status (ASD/ASD + ADHD vs. TDC/ADHD) and ADHD diagnostic status (ADHD/ASD + ADHD vs. TDC/ASD) entered as the between‐subjects factors. A nonsignificant interaction between the disorders is compatible with an additive model of comorbidity. Main effects and interactions at a significance level of p < .001; SCQ‐hyperactivity/impulsivity: ρ = .40, p < .001), these correlations were conducted on age and rating scale corrected scores. To correct for multiple correlations between rating scales and task performance parameters, Sidak‐adjusted p‐values were also applied. Differences in correlations between different performance measures were examined using Fisher's transformations.Where significant group differences were found, Spearman's correlations were conducted between the performance parameter and symptom scores. In order to account for the significant association between task performance parameters and age, as well as between ASD and ADHD symptoms in the sample  = 3.02, p < .001; Pillai's trace = .47]. Using Sidak‐corrected p‐values, univariate testing indicated a significant effect of group on MRT , RTSD , Tau  and CV .A significant multivariate effect of group emerged for task performance during the slow‐baseline condition  and more variable in responding . In addition, children with ASD made faster responses compared to ADHD  and ASD + ADHD  and were less variable in their responses compared to ADHD  and ASD + ADHD . There were no significant differences between ASD‐only and TDC (p > .05).Compared to TDC, children with ADHD and ASD + ADHD were slower . Using Sidak‐corrected p‐values, univariate testing indicated a significantly greater MRT , SD‐RT , Tau  and CV  in children with ADHD (ADHD/ASD + ADHD) compared to children without ADHD (TDC/ASD). There was no multivariate effect of ASD diagnosis . There was a trend towards a significant interaction between ASD and ADHD diagnoses , yet no performance measures met significance at Sidak‐corrected p‐values.When combined by diagnosis, there was a significant effect of group for ADHD diagnosis (ADHD/ASD + ADHD)  and a significant interaction between group and condition . Post hoc analyses revealed a significant difference by condition between (a) TDC and ADHD‐only  (b) TDC and ASD + ADHD , (c) ASD‐only and ADHD‐only  and (d) ASD‐only and ASD + ADHD , whereby there was a greater reduction in MRT from baseline to reward in the ADHD groups compared to the TDC and ASD‐only group  = 19.45, p < .001, d = 0.92, 95% CI = 0.49–1.35], indicating greater task performance improvement compared to children with no ADHD diagnosis. There was no interaction between condition and ASD diagnosis  and no interaction between ADHD and ASD diagnosis with condition .There was a main effect of diagnostic group  and a significant interaction between group and condition . Post hoc analyses revealed a significant difference by condition between (a) TDC and ADHD‐only ; (b) TDC and ASD + ADHD ; and (c) ASD‐only and ADHD‐only , indicating a greater reduction in RTSD from baseline to fast‐incentive conditions in the ADHD groups . When combined by diagnostic status, there was a significant interaction between condition and ADHD diagnosis , indicating greater task performance improvement compared to children with no ADHD diagnosis. There was no interaction between condition and ASD diagnosis  and no interaction between ADHD and ASD diagnosis with condition .There was a main effect of diagnostic group , indicating reduction in CV across all groups from baseline to fast‐incentive conditions. There was a main effect of diagnosis , but there was no interaction between group and condition on the CV  and a significant interaction between group and condition . Post hoc analyses revealed a significant difference between TDC and ADHD‐only , indicating a greater reduction in Tau from baseline to fast‐incentive conditions in the ADHD‐only group . When combined by diagnostic status, there was a significant interaction between condition and ADHD diagnosis , indicating greater task performance improvement compared to children with no ADHD diagnosis. There was no interaction between condition and ASD diagnosis  and no interaction between ADHD and ASD diagnosis with condition .There was a main effect of diagnostic group [r = .35, p = .001, Sidak‐corrected p = .007; hyperactivity/impulsivity r = .30, p = .004, Sidak‐corrected p = .08), CV  and Tau , with a trend for MRT . Difference scores calculated between baseline and fast‐incentive conditions indicated significant correlations with ADHD symptoms and SD‐RT  and Tau ; with a trend for MRT , Fisher's transformations indicated trend‐level differences in correlations between performance measures for (a) inattention and MRT versus inattention and CV ; (b) inattention and MRT improvement versus inattention and SD‐RT improvement ; and (c) hyperactivity/impulsivity and MRT versus hyperactivity/impulsivity and CV . There were no significant correlations between performance measures and ASD symptoms.Table This study investigated task performance across slow and fast‐incentive conditions in children with ASD, ADHD and co‐occurring ASD + ADHD, compared to typically developing controls, using a task that has been used in several previous studies of ADHD. Findings from categorical diagnoses and quantitative trait measures converge to suggest longer and more variable RTs are specific to ADHD in slower conditions compared to ASD, while no significant group differences are observed in faster and more rewarding conditions. Children with ADHD also demonstrated greater reduction in response speed and variability from baseline to fast‐incentive conditions in comparison to children with ASD and typically developing controls. Those with comorbid ASD + ADHD were largely similar in performance to children with ADHD, and analyses support an additive co‐occurrence of the unique disorders.The observation of longer and more variable RTs in children with ADHD (ADHD and ASD + ADHD) in the slow‐baseline condition, compared with children with ASD‐only and controls, is consistent with several previous studies that indicate the standard deviation of RT is a key marker of risk for the disorder  showed greater improvement in speed and variability of RT from the baseline to fast‐incentive condition, consistent with several studies , which exhibits greater activity during rest and shows strong negative correlations with ‘task‐positive’ networks that are involved in task performance. For example, in children with ADHD, deactivation of the DMN from rest‐to‐task is increased when offered high incentives compared to low incentives , yet four‐group comparisons of Tau improvement were not significant. Future work should directly examine the impact of intellectual ability according to the different conditions, particularly as discrepancies in IQ and other skills differ between these diagnostic groups  may be a transdiagnostic phenotype of ASD and ADHD.We compared task performance in children with ASD, ADHD and co‐occurring ASD + ADHD during slow and fast‐incentive task conditions, using standard and ex‐Gaussian analyses.Longer and more variable RTs were demonstrated in ADHD and ASD + ADHD in both conditions.Children with ADHD and ASD + ADHD demonstrated greater improvement in performance from slow to fast‐incentive conditions.Increased RTV and improvement under optimal conditions may be specific to ADHD.Appendix S1. Analyses with age and IQ included as covariates.Table S1. Correlations between RT parameters in baseline condition.Table S2. Correlations between RT parameters in fast‐incentive condition.Click here for additional data file.


N = 675 healthy adults. Life events and ADHD symptoms were assessed using questionnaires. The mediation of the association between life events and ADHD symptoms by memory bias was examined. We explored the roles of different types of life events and of ADHD symptom clusters. Life events and memory bias were associated with overall ADHD symptoms as well as inattention and hyperactivity/impulsivity symptom clusters. Memory bias mediated the association of Lifetime Life Events, specifically Childhood Trauma, with ADHD symptoms. Negatively biased memory may be a cognitive marker of the effects of Childhood Trauma on the development and/or persistence of ADHD symptoms.Stressful life events, especially Childhood Trauma, predict ADHD symptoms. Childhood Trauma and negatively biased memory are risk factors for affective disorders. The association of life events and bias with ADHD symptoms may inform about the etiology of ADHD. Memory bias was tested using a computer task in  Attention-deficit/hyperactivity disorder (ADHD) is prevalent in children , which consists of self-reported healthy mainly young adults. Subsamples of the current sample have previously been described elsewhere  sample .The Positive and Negative Affect Schedule  and proportion of self-referent positive recall (positive memory bias). The positive and negative memory bias variables were calculated by dividing the number of adjectives endorsed as self-referent and recalled in a given valence category by the total number of self-endorsed adjectives.p < .0083. Based on the correlations  = .22, p < .001, but not to the memory bias variables, all p > .07. When comparing men and women on the number of Lifetime Life Events and memory bias, we saw gender differences on both the positive and negative memory bias scores, t(673) = 3.33, p = .001 and t(673) = 2.02, p = .044, respectively.Complete data were available for 675 participants. Descriptives of the sample are shown in Table p < .001); both inattention and hyperactivity/impulsivity symptoms contributed to this correlation. A significant positive correlation was also seen between the Lifetime Life Events and Recent Stress variables, and total ADHD score (both p < .001). Both inattention and hyperactivity/impulsivity symptoms contributed to the correlation with Lifetime Life Events. Hyperactivity/impulsivity symptoms but not inattention symptoms were significantly correlated with Recent Stress . Furthermore, positive correlations were found for negative memory bias and Lifetime Life Events as well as Childhood Trauma (p < .005 for both), but not Recent Stress. None of the three life events variables correlated with positive memory bias. Therefore, mediation analyses were only run for negative memory bias. Also, because of the absence of correlations between Recent Stress and negative memory bias variable, mediation of the association of Recent Stress and ADHD symptoms by negative memory bias was not examined.The correlational structure of the independent and dependent variable data is given in Table p < .001 in the total effect model. The indirect effect ‘ab’ was small (0.005), but statistically significant as the bootstrapped unstandardized indirect effect 95% confidence interval (BCa CI) ranged from .002 to .01 (i.e. not including zero). The ratio of the indirect effect (referred to as PM) to the direct effect was .18. The PM value provides an effect size measure, and in this case it indicates that 18% of the effect of life events on ADHD symptoms operates indirectly through negative memory bias.In the following, negative memory bias was examined as a mediator of the association between life events and ADHD symptoms according to the model presented in Fig. M was .21 for Model 2 and .18 for Model 3.In separating the ADHD total scores into scores for the two different symptom domains, we found both the associations of Lifetime Life Events with inattention (IA) symptom score as well as with hyperactivity/impulsivity (HI) symptom score to be mediated by negative memory bias (see Table p = .059.When examining the associations with Childhood Trauma only (Model 4), we found that the direct effect of Childhood Trauma on negative memory bias was significant, but the direct effect of Childhood Trauma on total ADHD symptoms fell short of reaching statistical significance, with M = .49): early trauma strongly affected negative memory bias, but no significant direct effects on inattention symptoms were observed. For hyperactivity/impulsivity the pattern was different, with significant direct and indirect effects, and mediating memory bias explaining only approximately 21% of the effect.For the separate ADHD symptom domains, we observed an interesting pattern. As apparent from Table The current study substantiates earlier suggestive findings showing associations between life events and population ADHD symptoms, and shows that such associations might be particularly driven by childhood traumatic events. The associations were robust, when controlling for negative ‘depressotypic’ affect, and were observed for both inattention and hyperactivity/impulsivity. We provide new evidence for the mediation by negative memory bias of associations between life events and population ADHD symptom scores. This first exploration of the relevance of memory bias as marker for ADHD symptoms will hopefully stimulate further (sub)clinical research into cognitive biases in ADHD.p < .05. Although our results cannot address the direction of the association, they may indicate that while recent stressors can still exacerbate current symptom severity somewhat, Childhood Trauma—possibly through memory processes—may be a risk factor for both the development and persistence of ADHD symptoms into adulthood. The latter is important, since we still lack a good understanding of the factors that influence persistence of ADHD symptoms into adulthood. Persistence has for example been associated with childhood ADHD severity and whether or not patients received treatment during childhood , adding to the understanding of the role of Childhood Trauma in ADHD. However, the variance of recent stressful events and Childhood Trauma is limited in a healthy sample. Web-based data collection was used, which limits the controllability of data collection. However, testing participants in their natural setting eliminates experimenter effects (Harris and Rosenthal In conclusion, biased processing of emotional information may be a marker for adult ADHD symptom severity in addition to being a risk factor for depression onset, maintenance, and recurrence (De Raedt and Koster


N = 40; 7–13 years old) were tested with a hot and cold Stroop-like task. This was followed by a double-blind placebo-controlled crossover trial of the effect of MPH on these skills. Children with ADHD showed a specific difficulty inhibiting their responses, particularly to hot, angry and frustration-inducing stimuli. Further, treatment with MPH was effective in reducing errors toward frustration-inducing stimuli as compared to placebo , particularly with repeated exposure to the stimuli. Results indicate that children with ADHD experience executive control difficulties, particularly in hot negative emotional contexts. These emotion regulation difficulties are amenable to stimulant intervention.Attention deficit hyperactivity disorder (ADHD) is thought to involve an executive inhibitory control (IC) deficit, yet it is not clear if this is a general deficit affecting both cold and hot EC, and if methylphenidate (MPH) affects both systems in treated children. We explored this by using a Stroop-like task in children with ADHD as compared to controls, containing different types of emotional stimuli (six levels), and we investigated the role of intervention with MPH on IC as compared to placebo. Children with ADHD and controls ( Theories about attention deficit hyperactivity disorder (ADHD) emphasize a neonatal origin  that comDifficulties processing information have been suggested as an explanation for the impulsivity that is characteristic of ADHD . ResearcIndeed, neuropsychological literature and recent neuroscience data point to at least two distinct executive networks that are active already in early development , 18; oneNeural network differences in this regard are such that the cold system, responsible for updating, inhibition and flexibility, seems to activate the dorsolateral prefrontal cortex (DLPFC), along with mid-superior frontal gyrus, superior and inferior temporal gyrus and inferior parietal cortex network. The hot system on the other hand, enabling self-regulation, decision-making and emotion perception, activates more ventromedial and orbital prefrontal cortex areas , 25, aloResearch concentrating on the interrelations between these networks suggests that hot and cool EF rely on some shared and some different, yet interconnected prefrontal circuitry, with hot EF tasks involving moderation and interference from affective and reward processing regions, mostly through thalamic-limbic ventral striatum circuitry , 26. TheImaging data in children with ADHD suggest the involvement of both DLPFC and ventromedial prefrontal cortex (vmPFC) networks, along with these networks’ subcortical structures . It has The idea that the hot system is affected in ADHD is further supported by reports that explore this relationship on a behavioral level. Children and adolescents with ADHD experience deficits in processing emotional content –38, partIntegration of the above literature seems to point to the notion that executive control differences in ADHD may be particularly susceptible to tasks with hot content, possibly more so with negative valence, at school-age years. To examine this notion, and yet limit task impurity concerns , the curMPH, the most common treatment for ADHD, operates by blocking dopamine-active reuptake transporter and increasing extracellular dopamine proportionally to the level of blockade and to the rate of dopamine release . This prMPH has been shown to improve fine motor coordination, reaction time, memory, response inhibition, vigilance, impulse control, attention, concentration , as wellComparisons of cold and hot executive effects in ADHD are often limited by task impurity , makingThe paradigm enabled the investigation of two hypotheses: First, in 7- to 13-year-old children, the hot EC task, especially angry or frustration-inducing emotions, would be demanding for children with ADHD, as compared to the cold task.Second, MPH, as compared to no intervention and placebo, would moderate IC deficits more effectively, particularly in regulating responses that probe the hot network, by affecting arousal regulation, with an emphasis on negative valence.The current research explored ADHD effects on cold and hot EC in children with ADHD as compared to age-matched controls, and then employed a double-blind placebo-controlled crossover study investigating the effect of MPH on children with ADHD who underwent the same task.N = 20) and non-ADHD (N = 20) groups. All ADHD participants were referred by their community pediatricians for evaluation as required by the ministry of health guidelines. ADHD diagnosis was made by a pediatric neurologist specializing in ADHD in the child psychiatric department unit at the hospital according to the protocol employed in the clinic. Protocol included clinical evaluations, the Child Behavior Check List   = 10.884, p < .002, η2 = .232; disorganized F = 9.330, p < .004, η2 = .206].To explore ADHD differences in response to each stimulus type, repeated-measures analysis was conducted comparing cold, neutral, happy, sad, angry and disorganized stimuli as a function of ADHD, with age and aggression held as covariates. Results yielded an emotional valence by ADHD group interaction effect  and placebo  conditions. In order to account for potential learning affects, we computed differences between errors made in the non-medication condition administered first, and the intervention conditions.To assess overall intervention effects, repeated-measures analyses were run comparing total error rate as a function of intervention type. Results showed increased errors in the non-intervention condition, as compared to both MPH   and intervention difference score  as within-subject variables, and presentation order as a between-subjects variable. Age and aggression scores were held as covariates. Results indicated an intervention by order effect [67] Fig. , and no F = 3.521, p < .05, η2 = .615]  = 9.708, p < .01, η2 = .393].Additionally, a moderate-strong emotional valence × intervention interaction effect was noted [15] Fig. , with a F = 4.384, p < .05, η2 = .114], with children in the ADHD group responding more quickly than in the controls in this condition. Further intervention effect analyses, controlling for intervention order, along with the above covariates, yielded null results.Finally, the same model as above was applied to evaluate response times (RT) to correct answers in the task. The model included age and aggression as covariates. Results yielded group differences in responding to the happy condition [mean ± SD, for ADHD 605.88 ± 197.68, controls 679.87 ± 228.73; This study examined the notion that children with ADHD have more difficulty exerting inhibition in hot contexts, specifically those that induce anger and frustration. We explored this by investigating EF in a non-emotional and emotionally loaded inhibition task in 7- to 13-year-old children with ADHD as compared to controls, and further validated the notion by exploring MPH intervention effects using a double-blind placebo-controlled crossover design.In this fairly simple Stroop-like task, no ADHD main effect was noted in response to the cold stimuli. Results in the current report, with a simple low-frustration go task, show that cold IC in children with ADHD is preserved, yet when confronted with specific emotional valence, performance is compromised. Indeed, previous studies with 6- to 13-year-old children found no differences between ADHD and controls in response to a Stroop task  that incBy using one task to explore both cold and emotional stimuli, differences emerged between ADHD and controls in their error rates to angry and disorganized expressions, and in their response rates to the happy stimuli. Two potential interpretations may be considered with regard to this finding. The first may point to a particular deficit in the hot as compared to the cold EF system, activated by highly arousing negative stimuli. A specific deficit in hot EF has been noted in children with susceptible attention networks , 67. IntA somewhat different account may rely on the interdependence between the two EF networks. Cunningham and Zelazo’s neurological iterative reprocessing model , 69 suggResearch has suggested that high arousing negative stimuli are particularly potent in activating initial avoidance, while sad and happy stimuli promote a less clear approach/avoidance pattern . Taken tThe current difficulties in angry and frustration-inducing stimuli may contribute to the framework that suggests a unitary EF , with neFindings also resonate with reports from ecological settings of children with ADHD. Research notes deficits in emotional processing in children with ADHD  with regCurrent findings may also pertain to emotional regulation issues in ADHD. Previous work found that children with ADHD have greater difficulty identifying emotional stimuli, especially negative ones , 39, 77.This deficit may be relevant in understanding social relationships of children with ADHD. Their relationships are often characterized by impulsive responses, increased aggression and conflicts, as compared to children without ADHD , 79–81. The difficulty in executive control toward emotional stimuli seems compatible with imaging reports that suggest disturbances in ventromedial/orbital fronto-amygdala connections in ADHD . SpecifiThese results were also complimented in the current study with pharmacological intervention data. Current data point to an MPH effect when comparing error rates in response to stimuli loaded with different emotions. Responses indicated that children with ADHD benefit from MPH intervention, especially in regulating responses to disorganized stimuli (which were most affected as compared to controls), more so than placebo intervention. This finding further supports the notion that noradrenergic pathways in children with ADHD provide a more optimal base for regulating arousal and recruiting mental resources needed for executive control, particularly in negatively charged  or ambigThe literature so far has concentrated on repeated exposure to MPH and has understudied the interaction of intervention with repeated exposure of the stimuli, leading to greater levels of familiarity in order to reduce ambiguity aversion . CurrentIndeed, it has been suggested that efficacy of self-regulation in social interactions of children and young adolescents with ADHD is highly dependent upon contextual factors, and on the micro-sequence of events that proceed the response, particularly when events are negatively loaded . CurrentFuture work may explore further the influences of different dosages and different exposure durations, and their interaction with negative emotional valence and level of familiarity. This can further deepen our understanding of intervention type by valence interaction of executive regulation in children with ADHD.