The most recent functional neuroimaging studies on Tourette syndrome (TS) are reviewed in this paper. Although it can be difficult to compare functional neuroimaging studies due to differences in methods, differences in age of the included subjects, and differences in the extent to which the presence of comorbidity, medical treatment, and severity of tics are considered in the various studies; most studies show that the cortico-striato-thalamo-cortical circuit seems to be involved in the generation of tics. Changes in this circuit seem to be correlated with tic severity. Correlations have been found between the presence of tics and hypermetabolism in various brain regions. Abnormalities of GABAergic, serotonergic, and dopaminergic neurotransmission in patients with TS have been suggested. During tic suppression, increased activity in the inferior frontal gyrus is seen. The premotor cortex might be involved in inhibition of motor control in subjects with TS. The right anterior insula is suggested to be a part of the urge–tic network. Several studies have shown altered motor network activations and sensorimotor gating deficits in subjects with TS. In future studies, inclusion of more well-defined subjects and further examination of premonitory urge and tic suppression is needed in order to increase the knowledge about the pathophysiology and treatment possibilities of TS. Keywords: functional neuroimaging, Tourette syndrome
Among the estrogens that are biosynthesized in the human body, 17β-estradiol (estradiol or E2) is the most common and the best estrogen for neuroprotection in animal models of the central nervous system (CNS) injuries such as spinal cord injury (SCI), traumatic brain injury (TBI), and ischemic brain injury (IBI). These CNS injuries are not only serious health problems, but also enormous economic burden on the patients, their families, and the society at large. Studies from animal models of these CNS injuries provide insights into the multiple neuroprotective mechanisms of E2 and also suggest the possibility of translating the therapeutic efficacy of E2 in the treatment SCI, TBI, and IBI in humans in the near future. The pathophysiology of these injuries includes loss of motor function in the limbs, arms and their extremities, cognitive deficit, and many other serious consequences including life-threatening paralysis, infection, and even death. The potential application of E2 therapy to treat the CNS injuries may become a trend as the results are showing significant therapeutic benefits of E2 for neuroprotection when administered into the animal models of SCI, TBI, and IBI. This article describes the plausible mechanisms how E2 works with or without the involvement of estrogen receptors and provides an overview of the known neuroprotective effects of E2 in these three CNS injuries in different animal models. Because activation of estrogen receptors has profound implications in maintaining and also affecting normal physiology, there are notable impediments in translating E2 therapy to the clinics for neuroprotection in CNS injuries in humans. While E2 may not yet be the sole molecule for the treatment of CNS injuries due to the controversies surrounding it, the neuroprotective effects of its metabolite and derivative or combination of E2 with another therapeutic agent are showing significant impacts in animal models that can potentially shape the new treatment strategies for these CNS injuries in humans.
Since the modern description of primary progressive aphasia (PPA) more than 30 years ago, the interest in neurodegenerative conditions that selectively target the language network has grown exponentially. Fueled by advances in neuroimaging and biomarkers, progress in the field has brought new insights into clinical categorization, neural correlates of language, and pathological mechanisms of progression in PPA. Of relevance, the inception of logopenic progressive aphasia as an atypical presentation of Alzheimer's disease and the formalization of the international diagnostic criteria and classification of PPA represent milestones in the field. Paradoxically, those advances have also brought controversy and challenges. The application of the current classification in cases with mixed or very mild language deficits is still challenging, while the accurate pathological prediction at the individual level remains elusive. In addition, it is more evident now that nonlanguage deficits, including other cognitive and motor deficits, can appear early on and potentially assist in the differential diagnosis. From a historical perspective, this review addresses the conceptual evolution of PPA and the contribution that clinical refine - ments, cognitive neuropsychology, and pathology have made to the field.
Voxel-based morphometry (VBM) is a widely used automated technique for the analysis of neuroanatomical images. This work, which reviews important VBM clinical find- ings of the last few years, is divided into two main sections. After briefly introducing VBM methodology, in the first part, VBM findings on neurological and psychiatric diseases have been discussed separately. The reported studies were divided into studies that examine the diagnostic value of VBM results and their usefulness for the differential diagnosis between two disorders; studies investigating the potential of VBM for the diagnosis in an early stage of the illness, and studies that examine the utility of VBM for predicting the transition from prodromal phase to full-blown disease. In the second part, this review focuses on the most recent findings on the single-case approach. This analysis is useful for promoting the translational impact of VBM results in clinical practice, where clinicians need to make inferences at the level of the individual patient. Finally, within the single-case approach, a paragraph is dedicated to the potential forensic applications of VBM. Indeed, if used to support and integrate results obtained with classical forensic evaluations, VBM may provide objective data that could be used to reduce controversy in forensic psychiatric evaluations of mental insanity. In this second part, particular emphasis is given to the problem of results interpretation, which should be based mainly on the pres- ence of anatomoclinical correlation. The review finishes with a provocative note reporting an interesting result of a single-case VBM analysis that highlights the risk to fall into the "reverse inference" reasoning. This example has been chosen because it effectively highlights the risks
Altruism is an important social construct related to human relationships and the way many interpersonal and economic decisions are made. Recent progress in social neuroscience research shows that altruism is associated with a specific pattern of brain activity. The tendency to engage in altruistic behaviors is associated with greater activity within limbic regions such as the nucleus accumbens and anterior cingulate cortex in addition to cortical regions such as the medial prefrontal cortex and temporoparietal junction. Here, we review existing theoretical models of altruism as well as recent empirical neuroimaging research demonstrating how altruism is processed within the brain. This review not only highlights the progress in neuroscience research on altruism but also shows that there exist several open questions that remain unexplored.
Objective: The present study aimed to examine whether the story understanding of a nonexplanatory film affects mirror neuron system (MNS) activity and to discuss the interactive process involved in generating empathy for fictional characters during participants’ viewing of the film under natural viewing conditions. Methods: The material of the experiment was a Japanese film entitled Dolls . It is a nonexplanatory fiction film, in which the two (male and female) main characters show only minimal actions or facial expressions; therefore, the viewers hardly understand the story until it has been developed to some extent. We measured twelve participants’ MNS activity by using near-infrared spectroscopy during the viewing of the first 20 minutes of the film. Additionally, we measured the brain activity while performing their own hand and leg motions after viewing the film to identify their motor cortices. Results: The results showed that the viewer’s MNS activity increased gradually as the introductory part of the story developed. Subsequent analyses revealed a significant increase in MNS activity in the later chapters of the film at the right premotor and supplementary motor cortices ( P <0.05). Furthermore, there was a significant correlation between the MNS activity and the Interpersonal Reactivity Index scores ( P <0.05). Conclusion: These results indicate that the viewer’s MNS activity was enhanced by the story understanding of a fiction film. We suggest that MNS activity during viewing fiction films can be used as a measure of how much the story, and rhetoric of a narrative, induces empathy in the viewers even if characters show only minimal actions or facial expressions. Keywords: mirror neuron system, MNS, empathy, nonexplanatory film, story understanding, premotor cortex
Dual-process models from neuroscience suggest that addiction is driven by dysregulated interactions between bottom-up neural processes underpinning reward learning and top-down neural functions subserving executive function. Over time, drug use causes atrophy in prefrontally mediated cognitive control networks and hijacks striatal circuits devoted to processing natural rewards in service of compulsive seeking of drug-related reward. In essence, mindfulness-based interventions (MBIs) can be conceptualized as mental training programs for exercising, strengthening, and remediating these functional brain networks. This review describes how MBIs may remediate addiction by regulating frontostriatal circuits, thereby restoring an adaptive balance between these top-down and bottom-up processes. Empirical evidence is presented suggesting that MBIs facilitate cognitive control over drug-related automaticity, attentional bias, and drug cue reactivity, while enhancing responsiveness to natural rewards. Findings from the literature are incorporated into an integrative account of the neural mechanisms of mindfulness-based therapies for effecting positive behavior change in the context of addiction recovery. Implications of our theoretical framework are presented with respect to how these insights can inform the addiction therapy process. Keywords: mindfulness, frontostriatal, savoring, cue reactivity, hedonic dysregulation, reward, addiction
Neurophysiological and neuroanatomical studies have found that the same basic structural and functional organization of neuronal circuits exists throughout the cortex. This kind of cortical organization, termed canonical circuit, has been functionally demonstrated primarily by studies involving visual striate cortex, and then, the concept has been extended to different cortical areas. In brief, the canonical circuit is composed of superficial pyramidal neurons of layers II/III receiving different inputs and deep pyramidal neurons of layer V that are responsible for cortex output. Superficial and deep pyramidal neurons are reciprocally connected, and inhibitory interneurons participate in modulating the activity of the circuit. The main intuition of this model is that the entire cortical network could be modeled as the repetition of relatively simple modules composed of relatively few types of excitatory and inhibitory, highly interconnected neurons. We will review the origin and the application of the canonical cortical circuit model in the six sections of this paper. The first section (The origins of the concept of canonical circuit: the cat visual cortex) reviews the experiments performed in the cat visual cortex, from the origin of the concept of canonical circuit to the most recent developments in the modelization of cortex. The second (The canonical circuit in neocortex) and third (Toward a canonical circuit in agranular cortex) sections try to extend the concept of canonical circuit to other cortical areas, providing some significant examples of circuit functioning in different cytoarchitectonic contexts. The fourth section (Extending the concept of canonical circuit to economic decisions circuits) reviews the experiments conducted in humans by using transcranial magnetic stimulation to demonstrate the validity of the canonical cortical circuit model. The fifth section (Extending the concept of canonical circuit to economic decisions circuits) explores the hypothesis that also complex human behaviors such as economic decision-making could also be explained in terms of canonical cortical circuit. The final section (Conclusion) provides a critical point of view, evidencing the limits of the available data and tracking directions for future research. Keywords: canonical cortical circuit, cortex, cortical layers, cortical physiology
A biological system obtains information, reacts to stimuli, and modifies its behavior to adapt to the environment via complex control systems. A healthy system is expected to adequately adapt to a variety of changes. Physiological signals obtained from a healthy individual should contain rich information and complex behaviors. Entropy-derived measures have been used to access the complexity of the physiological signals. Aging or diseased status usually shows reduced entropy values and loss of complexity within the dynamics of physiological output. In this article, we aim to review the available evidence related to the pathophysiological nature of complexity and the clinical applications of entropy-derived measures in varied neurological disorders. Keywords: complexity, entropy, nerve system, electroencephalography, pathophysiology
Studied since antiquity, the human brain has recently been the inspiration for an international neuroscientific entrepreneurship, the Human Brain Project in Europe and the Brain Research through Advancing Innovative Neurotechnologies initiative in the USA. Different in their approach, both regard the human brain as one of the greatest challenges of 21st century science and the organ that makes us “human”. However, it is mainly the necessity of developing new therapies that affect up to a billion people worldwide, which has propelled the search for extensive expertise and investment in neuroscience research. The debate on ethical and social policy issues as well as the research and medical strategies of such gigantic efforts has involved participants as diverse as neuroscientists, philosophers, scholars in ethics and law, politicians, and the general public, rendering modern neuroscience an interdisciplinary and conflictual endeavor. In fact, the brain is described as the biological underpinning of our thoughts, emotions, perceptions, free willed actions, and memories, features unique to our humanity. In this review, three neuroscientists and a philosopher from the neuroethics community provide their perspectives for an up-to-date survey of salient neuroethical issues, ie, modulation of free will and neuropharmaceuticals and neurotechnologies that enhance cognitive capacities, as well as an introduction of the reader to the controversial new discipline of neuroethics. Written for nonexperts in the field, it is intended to reflect on and to impart information helpful in understanding the challenges and the perils of modern neuroscience, whose tools are so powerful as to jeopardize what is uniquely “human” through willful mind manipulation. We conclude that, for any future effort to “recreate” the mind and, at the same time, keep what is uniquely ours, it will be necessary to reflect ethically and review carefully man's past best efforts at self-understanding.
License. The full terms of the License are available at http://creativecommons.org/licenses/by-nc/3.0/. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. Permissions beyond the scope of the License are administered by Dove Medical Press Limited. Information on how to request permission may be found at: http://www.dovepress.com/permissions.php Neuroscience and Neuroeconomics 2015:4 51–60 Neuroscience and Neuroeconomics Dovepress
Cognitive enhancement with methylphenidate and modafinil: conceptual advances and societal implications Veljko Dubljevic,1 Christopher James Ryan2 1Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada; 2Discipline of Psychiatry and the Centre for Values, Ethics and the Law in Medicine, University of Sydney, Sydney, NSW, Australia Abstract: "Cognition enhancement" (CE) drugs are pharmaceuticals taken by healthy people with the aim of sustaining attention, augmenting memory, or improving other cognitive capacities. This paper focuses on two CE drugs – methylphenidate and modafinil. It analyzes their mechanism of action, the evidence for their efficacy in nonsleep deprived individuals, and reviews their adverse effects. It then addresses the normative stances and social issues surrounding CE drug use. Currently, there is little evidence that either methylphenidate or modafinil provide any useful cognitive enhancement to well-rested users. However, it is very possible that future research may reveal cognitive benefits for these agents or for other pharmaceuticals. Public attitudes on CE mirror those evident in academic debate. Even though the majority seem to be opposed to enhancement based on issues of authenticity, utility, and fairness, a steady minority take the view that cognitive enhancer usage is both acceptable and fair. Current legal regimes do not adequately address the social phenomenon of CE use. While the United Nations Convention on Psychotropic Substances defines limits of methylphenidate use across the globe, no such guide exists for modafinil. Keywords: cognitive enhancement, psychopharmacological neuroenhancement, Ritalin, Provigil, neuroethics
Research into Internet addiction (IA) has grown rapidly over the last decade. The topic has generated a great deal of debate, particularly in relation to how IA can be defined conceptually as well as the many methodological limitations. The present review aims to further elaborate and clarify issues that are relevant to IA research in a number of areas including: definition and characterization, incidence and prevalence rates, associated neuronal processes, and implications for treatment, prevention, and patient-specific considerations. It is concluded that there is no consensual definition for IA. Prevalence rates among nationally representative samples across several countries vary greatly (from 1% to 18.7%), most likely reflecting the lack of methodological consistency and conceptual rigor of the studies. The overlaps between IA and other more traditional substance-based addictions and the possible neural substrates implicated in IA are also highlighted. In terms of treatment and prevention, both psychological and pharmacological treatments are examined in light of existing evidence alongside particular aspects inherent to the patient perspective. Based on the evidence analyzed, it is concluded that IA may pose a serious health hazard to a minority of people.
Eating disorders are complex and serious psychiatric illnesses whose etiology includes psychological, biological, and social factors. Treatment of eating disorders is challenging as there are few evidence-based treatments and limited understanding of the mechanisms that result in sustained recovery. In the last 20 years, we have begun to identify neural pathways that are altered in eating disorders. Consideration of how these pathways may contribute to an eating disorder can provide an understanding of expected responses to treatments. Eating disorder behaviors include restrictive eating, compulsive overeating, and purging behaviors after eating. Eating disorders are associated with changes in many neural systems. In this targeted review, we focus on three cognitive processes associated with neurocircuitry differences in subjects with eating disorders such as reward, decision-making, and social behavior. We briefly examine how each of these systems function in healthy people, using Neurosynth meta-analysis to identify key regions commonly implicated in these circuits. We review the evidence for disruptions of these regions and systems in eating disorders. Finally, we describe psychiatric and psychological treatments that are likely to function by impacting these regions.
Although androgens are commonly seen as male sex hormones, it has been established over the years that in both sexes, androgens also respond to social challenges. To explain the socially driven changes in androgens, two theoretical models have been proposed: the biosocial model and the challenge hypothesis. These models are typically seen as partly overlapping; however, they generate different predictions that are clarified here. In humans, sports competi - tion and nonmetabolic competitive tasks have been used in the laboratory setting, as a proxy for agonistic interactions in animals. The results reviewed here show that the testosterone (T) response to competition in humans is highly variable - the studies present postcompetition T levels and changes in T that depend on the contest outcome and that cannot be predicted by the current theoretical models. These conflicting results bring to the foreground the importance of considering cognitive factors that could moderate the androgen response to competition. Among these variables, we elect cognitive appraisal and its components as a key candidate modulating factor. It is known that T also modulates the cognitive processes that are relevant to performance in competition. In this article, we reviewed the evidence arising from studies investigating the effect of administering exogenous T and compare those results with the findings from studies that measured endogenous T levels. Finally, we summarized the importance of also considering the interaction between androgens and other hormones, such as cortisol, when investigating the social modulation of T, as proposed by the dual-hormone hypothesis.
The neurobiological and computational analysis of value-based decision-making rests within the domain of neuroeconomics which has the goal of providing a biological account of human behavior relevant to both natural and social sciences. This review proposes a framework to investigate different aspects of the theoretical and molecular neurobiology of decision-making. In order to learn how to make good decisions, the brain needs to compute a separate value signal that measures the desirability of the outcomes that were generated by its previous decisions. The framework presented here combines aspects of current ideas relating to information processing by the hippocampal formation and how these relate to the phasic midbrain dopaminergic firing that occurs in response to the spatial and motivational aspects of rewarding events in the environment. The activities of hippocampal ensembles are considered to reflect a continuous updating process for attended experiences, defining both regular and irregular stimuli, environments, and actions, that are rapidly encoded as schemas into pre-existing knowledge bases. Keywords: hippocampus, schemas, synapse assemblies, cell assemblies, synapse plasticity
The aim of this review is to provide an overview of the research in attentional processing and affective reactivity in pregnancy and postpartum to inform future research. Numerous changes occur in attentional processing and affective reactivity across the childbearing period. This review focuses on the definition and methods of measuring attentional processing and affective reactivity. We discuss research studies that have examined the changes in these two processes during the perinatal phases of pregnancy and postpartum, with and without depression and anxiety. We evaluate the importance of using multiple levels of measurement, including physiological and neuroimaging techniques, to study these processes via implicit and explicit tasks. Research that has identified regions of brain activation using functional magnetic resonance imaging as well as other physiological assessments is integrated into the discussion. The importance of using sophisticated methodological techniques in future studies, such as multiple mediation models, for the purpose of elucidating mechanisms of change during these processes in pregnancy and postpartum is emphasized. We conclude with a discussion of the effect of these processes on maternal psychological functioning and infant outcomes. These processes support a strategy for individualizing treatment for pregnant and postpartum women suffering from depression and anxiety. Keywords: attentional processing, emotion, affective reactivity, depression, pregnancy, postpartum
In this article, we characterize the relationship between natural aging and risky decision making through an integration of cognitive, emotional, and neurobiological theories on the effects of natural aging. Based on the existing evidence, we propose that the positivity emotional bias in elderly adults steers them away from taking high risks and toward more conservative approaches during decision making as part of their positive emotional regulatory strategies. However, aging is also associated with marked declines in cognitive functioning, such as attention and working memory, as well as impaired reinforcement-based associative learning, which arises from anatomical and functional declines in the dopaminergic transmission systems and in distinct brain regions such as the dorsolateral prefrontal cortex and hippocampus. In consequence, elderly adults may deviate from their usual conservative stance and toward more risk-taking tendencies, as observed in a subset of studies, if the demands of the risk-taking task exceed their cognitive and learning capacities. More empirical investigations are needed to determine the key factors that influence elderly individuals' decision making and behavior in risky situations. Research in this field is likely to have important practical implications for the financial and medical decision making of elderly adults, as well as promoting designated help targeting the elderly population in making important life decisions. Keywords: risky decision making, aging, insula, cognition, dopaminergic system
Fear anticipates a challenge to one's well-being and is a reaction to the risk of harm. The expression of fear in the individual is a constellation of physiological, behavioral, cognitive, and experiential responses. Fear indicates risk and will guide adaptive behavior, yet fear is also fundamental to the symptomatology of most psychiatric disorders. Neuroimaging studies of normal and abnormal fear in humans extend knowledge gained from animal experiments. Neuroimaging permits the empirical evaluation of theory (emotions as response tendencies, mental states, and valence and arousal dimensions), and improves our understanding of the mechanisms of how fear is controlled by both cognitive processes and bodily states. Within the human brain, fear engages a set of regions that include insula and anterior cingulate cortices, the amygdala, and dorsal brain-stem centers, such as periaqueductal gray matter. This same fear matrix is also implicated in attentional orienting, mental planning, interoceptive mapping, bodily feelings, novelty and motivational learning, behavioral prioritization, and the control of autonomic arousal. The stereotyped expression of fear can thus be viewed as a special construction from combinations of these processes. An important motivator for understanding neural fear mechanisms is the debilitating clinical expression of anxiety. Neuroimaging studies of anxiety patients highlight the role of learning and memory in pathological fear. Posttraumatic stress disorder is further distinguished by impairment in cognitive control and contextual memory. These processes ultimately need to be targeted for symptomatic recovery. Neuroscientific knowledge of fear has broader relevance to understanding human and societal behavior. As yet, only some of the insights into fear, anxiety, and avoidance at the individual level extrapolate to groups and populations and can be meaningfully applied to economics, prejudice, and politics. Fear is ultimately a contagious social emotion. Keywords: amygdala, anxiety, arousal, autonomic, emotion, phobia
Cigarette smoking remains the leading preventable cause of death worldwide. Efforts to reduce smoking prevalence include changes to policies that are expected to have impacts on smoking behaviors. Plain packaging has been introduced as a method to reduce the appeal of smoking by removing such branding information as pack colors and brand logos from cigarette packages. Behavioral studies of plain packaging demonstrate reductions in the appeal of cigarette packages, changes in smoking behaviors, and expected reductions in smoking initiation. Neuroimaging studies of branding demonstrate that the neural systems of rewards and cognitive control are associated with processing brand information (eg, logos). Neuroimaging studies in smokers demonstrate that the neural systems of reward respond to images of cigarettes and are associated with reductions in cognitive control responses. The current review discusses the state of research on plain packaging in terms of a biopsychosocial model of addiction in which behavioral studies of plain packaging can identify psychological and social changes related to packaging, whereas neuroimaging studies can identify biological changes underlying the psychological and social impacts of packaging. Together, these studies show that plain packaging may reduce positive perceptions of smoking by reducing related reward responses in the brain, thus increasing the likelihood that smokers will be able to resist the urge to smoke, and perhaps quit smoking altogether. Keywords: smoking, plain packaging, neuroimaging, branding, reward
