Co-Planar Stereotaxic Atlas of the Human Brain—3-Dimensional Proportional System: An Approach to Cerebral Imaging, J. Talairach, P. Tournoux. Georg Thieme Verlag, New York (1988), 122 pp., 130 figs. DM 268

Thirty years of brain imaging research has converged to define the brain’s default network—a novel and only recently appreciated brain system that participates in internal modes of cognition Here we synthesize past observations to provide strong evidence that the default network is a specific, anatomically defined brain system preferentially active when individuals are not focused on the external environment Analysis of connectional anatomy in the monkey supports the presence of an interconnected brain system Providing insight into function, the default network is active when individuals are engaged in internally focused tasks including autobiographical memory retrieval, envisioning the future, and conceiving the perspectives of others Probing the functional anatomy of the network in detail reveals that it is best understood as multiple interacting subsystems The medial temporal lobe subsystem provides information from prior experiences in the form of memories and associations that are the building blocks of mental simulation The medial prefrontal subsystem facilitates the flexible use of this information during the construction of self-relevant mental simulations These two subsystems converge on important nodes of integration including the posterior cingulate cortex The implications of these functional and anatomical observations are discussed in relation to possible adaptive roles of the default network for using past experiences to plan for the future, navigate social interactions, and maximize the utility of moments when we are not otherwise engaged by the external world We conclude by discussing the relevance of the default network for understanding mental disorders including autism, schizophrenia, and Alzheimer’s disease

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The Brain's Default Network Anatomy, Function, and Relevance to Disease

Information about the basal ganglia has accumulated at a prodigious pace over the past decade, necessitating major revisions in our concepts of the structural and functional organization of these nuclei. From earlier data it had appeared that the basal ganglia served primarily to integrate diverse inputs from the entire cerebral cortex and to "funnel" these influences, via the ventrolateral thalamus, to the motor cortex (Allen & Tsukahara 1974, Evarts & Thach 1969, Kemp & Powell 1971). In particular, the basal

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Parallel Organization of Functionally Segregated Circuits Linking Basal Ganglia and Cortex

This paper describes FieldTrip, an open source software package that we developed for the analysis of MEG, EEG, and other electrophysiological data. The software is implemented as a MATLAB toolbox and includes a complete set of consistent and user-friendly high-level functions that allow experimental neuroscientists to analyze experimental data. It includes algorithms for simple and advanced analysis, such as time-frequency analysis using multitapers, source reconstruction using dipoles, distributed sources and beamformers, connectivity analysis, and nonparametric statistical permutation tests at the channel and source level. The implementation as toolbox allows the user to perform elaborate and structured analyses of large data sets using the MATLAB command line and batch scripting. Furthermore, users and developers can easily extend the functionality and implement new algorithms. The modular design facilitates the reuse in other software packages.

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FieldTrip: open source software for advanced analysis of MEG, EEG, and invasive electrophysiological data

I have developed "tennis elbow" from lugging this book around the past four weeks, but it is worth the pain, the effort, and the aspirin. It is also worth the (relatively speaking) bargain price. Including appendixes, this book contains 894 pages of text. The entire panorama of the neural sciences is surveyed and examined, and it is comprehensive in its scope, from genomes to social behaviors. The editors explicitly state that the book is designed as "an introductory text for students of biology, behavior, and medicine," but it is hard to imagine any audience, interested in any fragment of neuroscience at any level of sophistication, that would not enjoy this book. The editors have done a masterful job of weaving together the biologic, the behavioral, and the clinical sciences into a single tapestry in which everyone from the molecular biologist to the practicing psychiatrist can find and appreciate his or

Principles of Neural Science

Clinical Overview and Phenomenology of Movement Disorders

Reaction time and transcranial magnetic stimulation.

The pathophysiology of myoclonus

I. Overview of Conditions/Chemodenervation/Nerve Block Procedures: Focal Movement Disorders Dystonias Spasticity Sialorrhea Headache Pain Conditions Off Label Indications Peripheral Nerve Blocks Motor Point Blocks Botulinum Toxin/Chemodenervation Techniques II. Review of Chemodenervation Agents: Botulinum Toxins Alcohol/Phenol III. Ultrasound Review: Basics of Ultrasound Technology Physics, Machine Settings, Artifacts Scanning Techniques Procedural Guidance Techniques: Neurotoxin Injections, Nerve Blocks. DVD Ultrasound Atlas I. Muscle Identification Section: Photos/Cine-loops Head and Neck Upper Limb Lower Limb Trunk. II. Procedure Atlas Muscle/Neurotoxin Injections Common/Less Common Techniques for Nerve/Motor Point Blocks.

Ultrasound-Guided Chemodenervation Procedures: Text and Atlas

Transcranial magnetic stimulation (TMS) is an exciting new tool for clinical neurophysiology (Hallett, 2000). Although it followed quickly on the heels of transcranial electrical stimulation, TMS has only been around for approximately 15 years. In this time, its use has expanded rapidly. At first, it was applied simply to the motor cortex to produce motor evoked potentials. This allowed measurement of central motor conduction times in the corticospinal tract. This capability is clearly valuable and has been applicable immediately in the clinic to the assessment of situations such as multiple sclerosis, cervical spondylosis, and primary lateral sclerosis. It became rapidly clear, however, that its value far exceeded the ability to measure central motor conduction. It was able to localize muscle representations and allowed mapping of the motor strip. Using a variety of clever procedures, it became possible to assess excitability in various ways, including the ability to determine intracortical networks of excitation and inhibition. The physiologic insights are increasingly exposing the great complexity of cortical processing. The value of TMS is not limited to its study of the motor cortex. Studies have shown that it can be used to study many regions including visual cortex, somatosensory cortex, and areas of parietal and frontal cortex with functions including language and memory. Transcranial magnetic stimulation can be used to excite or to inhibit different regions transiently. Its ability to inhibit regions of cortex transiently is particularly valuable because this allows a temporary, reversible “lesion” of the normal human brain. This capability has permitted conclusions relating to the functional relevance of different brain regions for specific functions (Cohen et al., 1997). Note that this conclusion cannot necessarily be made with neuroimaging, such as the popular functional MRI. Imaging studies say that a region is involved in a particular task, but not that it is critical for that task. Using all these methods, it has been possible to gather important insights into the pathophysiology of neurologic disorders. Disorders of the motor system have been most investigated, but other conditions such as epilepsy and migraine have also been studied. TMS has also been an excellent tool to study brain plasticity in situations such as stroke and recovery of function (Hallett, 2001). The next step was made when it was recognized that TMS may well influence the function of the brain even after the stimulation was finished (Wassermann and Lisanby, 2001). In general, slow rates of repetitive TMS tend to suppress function, whereas a rapid rate enhances it. Psychiatrists have jumped quickly onto this possibility and see in TMS a new tool that may replace electroconvulsive therapy. Transcranial magnetic stimulation may also improve symptoms in patients with motor system disorders such as Parkinson’s disease or dystonia. Transcranial magnetic stimulation is a safe technique. With single pulses and paired (double) pulses, there has not been any problem with TMS at all. In rare individuals with brain lesions and a tendency to epilepsy, single pulses have apparently triggered a seizure, but even trying to trigger seizures in epileptic patients has been difficult. Repetitive stimulation at high rates, if given for long periods or with intense stimulation, can produce seizures even in normal individuals. Thus, repetitive stimulation needs to be given with care. There are guidelines published for safe stimulation parameters, and when these are followed, repetitive stimulation can be used safely with confidence (Wassermann, 1998). Although TMS is making great strides in research achievements, its application to the clinic so far, although distinct, has been limited. It is partly for this reason that in the United States, TMS remains a research procedure. It is necessary for clinical neurophysiologists to get approval of their institutional review board (ethics committee). When doing procedures of greater than usual risk, the Food and Drug Administration may also require an investigational device exemption. It will require a notable effort on the part of a manufacturer to demonstrate the utility (and corresponding safety) of the method. Meanwhile, in many other countries, TMS is readily available in the clinic. In this special issue of the Journal of Clinical Neurophysiology experts have summarized current knowledge Journal of Clinical Neurophysiology 19(4):253–254, Lippincott Williams & Wilkins, Inc., Philadelphia © 2002 American Clinical Neurophysiology Society

Mark Hallett

Papers

Clinical Overview and Phenomenology of Movement Disorders

Reaction time and transcranial magnetic stimulation.

The pathophysiology of myoclonus

Ultrasound-Guided Chemodenervation Procedures: Text and Atlas

Transcranial magnetic stimulation: a revolution in clinical neurophysiology.