Mark Hallett

Bio: Mark Hallett is an academic researcher from National Institutes of Health. The author has contributed to research in topics: Transcranial magnetic stimulation & Motor cortex. The author has an hindex of 186, co-authored 1170 publications receiving 123741 citations. Previous affiliations of Mark Hallett include Government of the United States of America & Armed Forces Institute of Pathology.

Clinical features of patients with blepharospasm: a report of 240 patients

Abstract: Background and purpose:To characterize patients with benign essential blepharospasm (BEB) by diagnosis, environmental risk factors, and family history. Methods:Two hundred and forty patients with BEB were evaluated through a clinical examination and questionnaire. The questionnaire reviewed personal medical history, demographic factors, risk factors for the development of blepharospasm and family history of dystonia and other neurological conditions. Results:Benign essential blepharospasm was more commonly found in women (2.8:1) and 93% of the patients were Caucasian. Fifty percent had pure BEB, 31% had BEB/Meige!s syndrome, and 4% had BEB and eyelid opening apraxia (+/)Meige!s syndrome). A minority of patients reported preceding photophobia (25%) or other eye conditions (22%). The majority were non-smokers, had no exposure to anti-emetic or antipsychotic agents, had a normal birth history, and had no history of head trauma. Seventy-two percent did report a stressful event immediately prior to the development of symptoms. Treatments reported included botulinum toxin (BoNT), oral medications, surgical procedures, and acupuncture. Thirty-two percent of patients reported a family history of focal dystonia, and BEB was the most commonly reported. Conclusion:This study confirms previous reports of usual age, sex, ca!eine and tobacco use, and family history in patients with blepharospasm. New findings include a report on occupation, lower reports of preceding eye conditions and photophobia, and higher reported stressful events. Further, this study shows a change in treatment with an increase in BoNT use and decrease in surgical procedures.

Non-invasive brain stimulation for Parkinson's disease: Current concepts and outlook 2015.

Abstract: BACKGROUND AND PURPOSE In advanced Parkinson's disease (PD), the emergence of symptoms refractory to conventional therapy poses a therapeutic challenge. The success of deep brain stimulation (DBS) and advances in the understanding of the pathophysiology of PD have raised interest in non-invasive brain stimulation as an alternative therapeutic tool. The rationale for its use draws from the concept that reversing abnormalities in brain activity and physiology thought to cause the clinical deficits may restore normal functioning. Currently the best evidence in support of this concept comes from DBS, which improves motor deficits, and modulates brain activity and motor cortex physiology, though whether a causal interaction exists remains largely undetermined. CONCLUSION Most trials of non-invasive brain stimulation in PD have applied repetitive transcranial magnetic stimulation (rTMS) targeting the primary motor cortex and cortical areas of the motor circuit. Published studies suggest a possible therapeutic potential of rTMS and transcranial direct current stimulation (tDCS), but clinical effects so far have been small and negligible regarding functional independence and quality of life. Approaches to potentiate the efficacy of rTMS, including increasing stimulation intensity and novel stimulation parameters, derive their rationale from studies of brain physiology. These novel parameters simulate normal firing patterns or act on the hypothesized role of oscillatory activity in the motor cortex and basal ganglia in motor control. There may also be diagnostic potential of TMS in characterizing individual traits for personalized medicine.

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

Abstract: 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

Parallel Organization of Functionally Segregated Circuits Linking Basal Ganglia and Cortex

Abstract: 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

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

Abstract: 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.

Principles of Neural Science

Abstract: 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