Brain-machine interfaces: an overview <s>  <s> In primates, sensory input can generate reflex motor cortex output in association with learned movement when the sensory input has a strong and direct connection to the motor cortex—for example, when a stimulus calling for repositioning of the hand consists of a perturbation of hand position. This finding supports the proposal that neurons of primate motor cortex may function in a transcortical servo-loop. <s> BIB001 </s> Brain-machine interfaces: an overview <s>  <s> There is growing public awareness of the ethical issues raised by progress in many areas of neuroscience. This commentary reviews the issues, which are triaged in terms of their novelty and their imminence, with an exploration of the relevant ethical principles in each case. <s> BIB002 </s> Brain-machine interfaces: an overview <s>  <s> The aims of this paper are to (i) provide a brief history of cochlear implants; (ii) present a status report on the current state of implant engineering and the levels of speech understanding enabled by that engineering; (iii) describe limitations of current signal processing strategies and (iv) suggest new directions for research. With current technology the “average” implant patient, when listening to predictable conversations in quiet, is able to communicate with relative ease. However, in an environment typical of a workplace the average patient has a great deal of difficulty. Patients who are “above average” in terms of speech understanding, can achieve 100% correct scores on the most difficult tests of speech understanding in quiet but also have significant difficulty when signals are presented in noise. The major factors in these outcomes appear to be (i) a loss of low-frequency, fine structure information possibly due to the envelope extraction algorithms common to cochlear implant signal processing; (ii) a limitation in the number of effective channels of stimulation due to overlap in electric fields from electrodes, and (iii) central processing deficits, especially for patients with poor speech understanding. Two recent developments, bilateral implants and combined electric and acoustic stimulation, have promise to remediate some of the difficulties experienced by patients in noise and to reinstate low-frequency fine structure information. If other possibilities are realized, e.g., electrodes that emit drugs to inhibit cell death following trauma and to induce the growth of neurites toward electrodes, then the future is very bright indeed. <s> BIB003 </s> Brain-machine interfaces: an overview <s>  <s> The cognitive neural prosthetic (CNP) is a very versatile method for assisting paralyzed patients and patients with amputations. The CNP records the cognitive state of the subject, rather than signals strictly related to motor execution or sensation. We review a number of high-level cortical signals and their application for CNPs, including intention, motor imagery, decision making, forward estimation, executive function, attention, learning, and multi-effector movement planning. CNPs are defined by the cognitive function they extract, not the cortical region from which the signals are recorded. However, some cortical areas may be better than others for particular applications. Signals can also be extracted in parallel from multiple cortical areas using multiple implants, which in many circumstances can increase the range of applications of CNPs. The CNP approach relies on scientific understanding of the neural processes involved in cognition, and many of the decoding algorithms it uses also have parallels to underlying neural circuit functions. <s> BIB004 </s> Brain-machine interfaces: an overview <s>  <s> Purpose of the Review ::: Auditory prostheses use electric currents on multiple electrodes to stimulate auditory neurons and recreate auditory sensations in deaf people. Cochlear implants have restored hearing in more than 200,000 deaf adults and children to a level that allows most to understand speech. Here we review the reasons underlying these results and describe new directions in restoring hearing to additional patient populations and the design of new devices. <s> BIB005 </s> Brain-machine interfaces: an overview <s>  <s> The steadily growing field of brain-computer interfacing (BCI) may develop useful technologies, with a potential impact not only on individuals, but also on society as a whole. At the same time, the development of BCI presents significant ethical and legal challenges. In a workshop during the 4th International BCI meeting (Asilomar, California, 2010), six panel members from various BCI laboratories and companies set out to identify and disentangle ethical issues related to BCI use in four case scenarios, which were inspired by current experiences in BCI laboratories. Results of the discussion are reported in this article, touching on topics such as the representation of persons with communication impairments, dealing with technological complexity and moral responsibility in multidisciplinary teams, and managing expectations, ranging from an individual user to the general public. Furthermore, we illustrate that where treatment and research interests conflict, ethical concerns arise. On the basis of the four case scenarios, we discuss salient, practical ethical issues that may confront any member of a typical multidisciplinary BCI team. We encourage the BCI and rehabilitation communities to engage in a dialogue, and to further identify and address pressing ethical issues as they occur in the practice of BCI research and its commercial applications. <s> BIB006
1) motor, 2) sensory, and 3) bidirectional (sensorimotor). This classification resembles a simplified model of the nervous system that labels areas as "sensory" or "motor". In reality, very few brain areas can be considered purely motor or purely sensory. Sensory and motor functions are intermixed in the brain, so the term "sensorimotor" is more appropriate for most of the areas  BIB001 . Recently developed bidirectional BMIs can be viewed as a model of such conjoint sensorimotor processing  . The development of BMIs has been nothing short of spectacular in recent years. We have seen an exponential growth in BMI publications. Many of the published results were entertained exclusively in science fiction not so long ago, and nobody expected that they would become real so soon. Notwithstanding the success of proof of concept BMI demonstrations, a large number of these projects are at the stage of laboratory testing, and years of research will be required for them to translate to clinical arena and consumer applications. One notable exception is the cochlear implant, which has been extremely successful BIB005 BIB003 . The prospect of BMIs intruding into the content of our minds, reading out thoughts and altering neural processing brings about ethical issues BIB002 BIB006 . For instance, how to prevent unwanted interactions of BMIs with the representation of self and free will? Such questions are particularly pertinent to BMIs that operate in cognitive domain, such as BMIs that decode decisions BIB004 and handle memories [17] . Although many of ethical issues related to BMIs seem far-fetched today, these questions will certainly become much more important in the future, when the development of artificial parts for the brain accelerates.