Extending, changing, and explaining the brain

This paper addresses concerns raised recently by Datteri (Biol Philos 24:301–324, 2009) and Craver (Philos Sci 77(5):840–851, 2010) about the use of brain-extending prosthetics in experimental neuroscience. Since the operation of the implant induces plastic changes in neural circuits, it is reasonable to worry that operational knowledge of the hybrid system will not be an accurate basis for generalisation when modelling the unextended brain. I argue, however, that Datteri’s no-plasticity constraint unwittingly rules out numerous experimental paradigms in behavioural and systems neuroscience which also elicit neural plasticity. Furthermore, I propose that Datteri and Craver’s arguments concerning the limitations of prosthetic modelling in basic neuroscience, as opposed to neuroengineering, rests on too narrow a view of the ways models in neuroscience should be evaluated, and that a more pluralist approach is needed. I distinguish organisational validity of models from mechanistic validity. I argue that while prosthetic models may be deficient in the latter of these explanatory virtues because of neuroplasticity, they excel in the former since organisational validity tracks the extent to which a model captures coding principles that are invariant with plasticity. Changing the brain, I conclude, is one viable route towards explaining the brain.     

Neural correlations, population coding and computation

How the brain encodes information in population activity, and how it combines and manipulates that activity as it carries out computations, are questions that lie at the heart of systems neuroscience. During the past decade, with the advent of multi-electrode recording and improved theoretical models, these questions have begun to yield answers. However, a complete understanding of neuronal variability, and, in particular, how it affects population codes, is missing. This is because variability in the brain is typically correlated, and although the exact effects of these correlations are not known, it is known that they can be large. Here, we review studies that address the interaction between neuronal noise and population codes, and discuss their implications for population coding in general.     

Molecules to minds: grand challenges for the 21st century

The Institute of Medicine's Forum on Neuroscience and Nervous System Disorders established a "Grand Challenges Initiative." The goal is to help frame a broad, integrated research program that would attract substantial funding and generate additional resources to support large-scale efforts to tackle some of the most daunting but important neuroscience questions.     

Development and function of the midbrain dopamine system: what we know and what we need to

The past two decades have seen an explosion in our understanding of the origin and development of the midbrain dopamine system. Much of this work has been focused on the aspects of dopamine neuron development related to the onset of movement disorders such as Parkinson's disease, with the intent of hopefully delaying, preventing or fixing symptoms. While midbrain dopamine degeneration is a major focus for treatment and research, many other human disorders are impacted by abnormal dopamine, including drug addiction, autism and schizophrenia. Understanding dopamine neuron ontogeny and how dopamine connections and circuitry develops may provide us with key insights into potentially important avenues of research for other dopamine‐related disorders. This review will provide a brief overview of the major molecular and genetic players throughout the development of midbrain dopamine neurons and what we know about the behavioral‐ and disease‐related implications associated with perturbations to midbrain dopamine neuron development. We intend to combine the knowledge of two broad fields of neuroscience, both developmental and behavioral, with the intent on fostering greater discussion between branches of neuroscience in the service of addressing complex cognitive questions from a developmental perspective and identifying important gaps in our knowledge for future study.     

Critical mass: The rise of a touchscreen technology community for rodent cognitive testing

The rise in the number of users and institutions utilizing the rodent touchscreen technology for cognitive testing over the past decade has prompted the need for knowledge mobilization and community building. To address the needs of the growing touchscreen community, the first international touchscreen symposium was hosted at Western University. Attendees from around the world attended talks from expert neuroscientists using touchscreens to examine a vast array of questions regarding cognition and the nervous system. In addition to the symposium, a subset of attendees was invited to partake in a hands-on training course where they received touchscreen training covering both hardware and software components. Beyond the two touchscreen events, virtual platforms have been developed to further support touchscreen users: (a) Mousebytes.ca , which includes a data repository of rodent touchscreen tasks, and (b) Touchscreencognition.org , an online community with numerous training and community resources, perhaps most notably a forum where members can ask and answer questions. The advantages of the rodent touchscreen technology for cognitive neuroscience research has allowed neuroscientists from diverse backgrounds to test specific cognitive processes using well-validated and standardized apparatus, contributing to its rise in popularity and its relevance to modern neuroscience research. The commitment of the touchscreen community to data, task development and information sharing not only ensures an expansive future of the use of rodent touchscreen technology but additionally, quality research that will increase translation from preclinical studies to clinical successes.     

Linking neuroscience and psychoanalysis from a developmental perspective: Why and how?

This paper aims to develop the rational to support why and how we should link neuroscience and psychoanalysis. Many of these points are derived from child development and child psychiatry. Neuroscience investigates developmental questions in a different way than psychoanalysis, while psychoanalysis itself has shifted towards new developmental paradigms. The rapprochement between neuroscience and psychoanalysis allows a new understanding of some concepts, including embodiment of mind, consciousness and attachment. The “double reading” paradigm allows a better understanding of symptomatic configurations. Linking neuroscience and psychoanalysis may improve treatments and result in new experimental neuroscientific paradigms involving changing the research object, changing the state of the research object, and investigating the structural changes in the brain following psychotherapy. The last aim is to create an epistemology of the articulation between the theoretical frameworks through phenomenology, “complementarism” and neuropsychoanalysis. We argue that it is necessary for clinicians to be aware of the advancements in each field. This is not only an epistemological question; we assume that new findings in neuroscience will change the way psychoanalysts think and approach treatment of their patients. We hope the present research will contribute to change the way that neuroscientists think and will provide new options to their set of experimental paradigms.     

Activated cortical states: Experiments, analyses and models

In awake animals, the cerebral cortex displays an "activated" state, with distinct characteristics compared to other states like slow-wave sleep or anesthesia. These characteristics include a sustained depolarized membrane potential (V(m)) and irregular firing activity. In the present paper, we evaluate our understanding of cortical activated states from a computational neuroscience point of view. We start by reviewing the electrophysiological characteristics of activated cortical states based on recordings and analysis performed in awake cat association cortex. These analyses show that cortical activity is characterized by an apparent Poisson-distributed stochastic dynamics, both at the single-cell and population levels, and that single cells display a high-conductance state dominated by inhibition. We next overview computational models of the "awake" cortex, and perform the same analyses as in the experiments. Many properties identified experimentally are indeed reproduced by models, such as depolarized V(m), irregular firing with apparent Poisson statistics, and the determinant role of inhibitory fluctuations on spiking. However, other features are not well reproduced, such as firing statistics and the conductance state of the membrane, suggesting that the network state displayed by models is not entirely correct. We also show how networks can approach a correct conductance state, suggesting ways by which future models will generate activity fully consistent with experimental data.     

A computational model for feature binding

The "Binding Problem" is an important problem across many disciplines, including psychology, neuroscience, computational modeling, and even philosophy. In this work, we proposed a novel computational model, Bayesian Linking Field Model, for feature binding in visual perception, by combining the idea of noisy neuron model, Bayesian method, Linking Field Network and competitive mechanism. Simulation Experiments demonstrated that our model perfectly fulfilled the task of feature binding in visual perception and provided us some enlightening idea for future research.     

Choices in neuroscience careers

How do I choose a mentor? How do I decide what field of neuroscience to work in? Should I consider doing research in industry? Most students and postdoctoral researchers aiming for a successful career in neuroscience ask themselves these questions. In this article, Nature Reviews Neuroscience asks four successful neuroscientists for their thoughts on the factors one should consider when making these decisions. We hope that this Viewpoint will serve as a useful resource for junior neuroscientists who have to make important and sometimes difficult decisions that might have long-lasting consequences for their careers.     

The social network: Neural control of sex differences in reproductive behaviors,motivation, and response to social isolation

Social animal species present a vast repertoire of social interactions when encountering conspecifics. Reproduction-related behaviors, such as mating, parental care, and aggression, are some of the most rewarding types of social interactions and are also the most sexually dimorphic ones. This review focuses on rodent species and summarizes recent advances in neuroscience research that link sexually dimorphic reproductive behaviors to sexual dimorphism in their underlying neuronal circuits. Specifically, we present a few possible mechanisms governing sexually-dimorphic behaviors, by hypothalamic and reward-related brain regions. Sex differences in the neural response to social isolation in adulthood are also discussed, as well as future directions for comparative studies with naturally solitary species.     

An Australian Brain Bank: a critical investment with a high return!

Research into neuropsychiatric disorders, including alcohol-related problems, is limited in part by the lack of appropriate animal models. However, the development of new technologies in pathology and molecular biology means that many more questions can be addressed using appropriately stored human brain tissues. The New South Wales Tissue Resource Centre (TRC) in the University of Sydney (Australia) is a human brain bank that can provide tissues to the neuroscience research community studying alcohol-related brain disorders, schizophrenia, depression and bipolar disorders. Carefully standardised operational protocols and integrated information systems means that the TRC can provide high quality, accurately characterised, tissues for research. A recent initiative, the pre-mortem donor program called "Using our Brains", encourages individuals without neuropsychiatric illness to register as control donors, a critical group for all research. Community support for this program is strong with over 2,000 people registering their interest. Discussed herein are the protocols pertaining to this multifaceted facility and the benefits of investment, both scientific and financial, to neuroscience researchers and the community at large.     

Response to Video and Computer-animated Images by the Tiger Barb, Puntius tetrazona

Video playback has become an important tool for testing certain questions about animal visual perception. While a few studies have compared the response of test subjects to live and video stimuli, it is generally assumed a priori that the animals will respond to the video image as if it were real. Since video devices are tuned to the spectral sensitivities and flicker fusion frequencies of the human eye and brain, it is important to conduct preliminary tests to compare the response of test subjects between live and video images. Here we compare schooling behavior of tiger barbs, Puntius tetrazona, when presented with a school of live fish, an analog video school of fish and a video of a computer-animated school of fish. Test subjects did not show a significantly different schooling behavior response to any of these stimuli. Additionally, when given the choice of schooling with a conspecific versus a heterospecific, tiger barbs schooled significantly more often with the conspecifics for all three stimulus formats. This study provides evidence that tiger barbs do not choose to discriminate between live and video models of fish and that this technique can be used to test future questions concerning visual perception for this species.     

Moving beyond dichotomies: Liao,S. Matthew (ed.), Moral Brains: The Neuroscience of Morality,Oxford University Press, 2016

Matthew Liao’s edited collection Moral Brains: The Neuroscience of Morality covers a wide range of issues in moral psychology. The collection should be of interest to philosophers, psychologist, and neuroscientists alike, particularly those interested in the relation between these disciplines. I give an overview of the content and major themes of the volume and draw some important lessons about the connection between moral neuroscience and normative ethics. In particular, I argue that moving beyond some of the dichotomies implicit in some of the debates advanced in the book makes the neuroscience of moral judgment much more useful in advancing normative ethics.     

Responsibility in the life sciences: assessing the role of professional codes

In response to threats from bioweapons, questions are being asked today in some countries about the implications and appropriateness of biological research. Many organizations and governments have suggested that bioscientists adopt what is generally referred to as a "code of conduct" to reduce the security concerns associated with their work. This article examines the potential contribution of such codes. By drawing on past lessons in other areas of professional life, it suggests some key questions, issues, and dilemmas for future consideration. As argued, attempts to establish codes must address demanding questions about their aims and audience--questions whose answers depend on potentially contentious issues regarding arms control, science, ethics, and politics.     

Carl F. Craver, Explaining what? Review of explaining the brain: mechanisms and the mosaic unity of neuroscience

Carl Craver’s recent book offers an account of the explanatory and theoretical structure of neuroscience. It depicts it as centered around the idea of achieving mechanistic understanding, i.e., obtaining knowledge of how a set of underlying components interacts to produce a given function of the brain. Its core account of mechanistic explanation and relevance is causal-manipulationist in spirit, and offers substantial insight into casual explanation in brain science and the associated notion of levels of explanation. However, the focus on mechanistic explanation leaves some open questions regarding the role of computation and cognition.     

How do high-level specifications of the brain relate to variational approaches?

High-level specification of how the brain represents and categorizes the causes of its sensory input allows to link "what is to be done" (perceptual task) with "how to do it" (neural network calculation). In this article, we describe how the variational framework, which encountered a large success in modeling computer vision tasks, has some interesting relationships, at a mesoscopic scale, with computational neuroscience. We focus on cortical map computations such that "what is to be done" can be represented as a variational approach, i.e., an optimization problem defined over a continuous functional space. In particular, generalizing some existing results, we show how a general variational approach can be solved by an analog neural network with a given architecture and conversely. Numerical experiments are provided as an illustration of this general framework, which is a promising framework for modeling macro-behaviors in computational neuroscience.     

For the law, neuroscience changes nothing and everything

The rapidly growing field of cognitive neuroscience holds the promise of explaining the operations of the mind in terms of the physical operations of the brain. Some suggest that our emerging understanding of the physical causes of human (mis)behaviour will have a transformative effect on the law. Others argue that new neuroscience will provide only new details and that existing legal doctrine can accommodate whatever new information neuroscience will provide. We argue that neuroscience will probably have a transformative effect on the law, despite the fact that existing legal doctrine can, in principle, accommodate whatever neuroscience will tell us. New neuroscience will change the law, not by undermining its current assumptions, but by transforming people's moral intuitions about free will and responsibility. This change in moral outlook will result not from the discovery of crucial new facts or clever new arguments, but from a new appreciation of old arguments, bolstered by vivid new illustrations provided by cognitive neuroscience. We foresee, and recommend, a shift away from punishment aimed at retribution in favour of a more progressive, consequentialist approach to the criminal law.