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Nature Reviews. Neuroscience Nov 2011Despite its clinical relevance, direct electrical stimulation (DES) of the human brain is surprisingly poorly understood. Although we understand several aspects of... (Review)
Review
Despite its clinical relevance, direct electrical stimulation (DES) of the human brain is surprisingly poorly understood. Although we understand several aspects of electrical stimulation at the cellular level, surface DES evokes a complex summation effect in a large volume of brain tissue, and the effect is difficult to predict as it depends on many local and remote physiological and morphological factors. The complex stimulation effects are reflected in the heterogeneity of behavioural effects that are induced by DES, which range from evocation to inhibition of responses - sometimes even when DES is applied at the same cortical site. Thus, it is a misconception that DES - in contrast to other neuroscience techniques - allows us to draw unequivocal conclusions about the role of stimulated brain areas.
Topics: Brain Mapping; Cerebral Cortex; Electric Stimulation; Humans
PubMed: 22127300
DOI: 10.1038/nrn3140 -
Journal of Neuroscience Methods Nov 2018The human motor cortex can be mapped safely and painlessly with transcranial magnetic stimulation (TMS) to explore neurophysiology in health and disease. Human error...
BACKGROUND
The human motor cortex can be mapped safely and painlessly with transcranial magnetic stimulation (TMS) to explore neurophysiology in health and disease. Human error likely contributes to heterogeneity of such TMS measures. Here, we aimed to use recently pioneered robotic TMS technology to develop an efficient, reproducible protocol to characterize cortical motor maps in a pediatric population.
NEW METHOD
Magnetic resonance imaging was performed on 12 typically developing children and brain reconstructions were paired with the robotic TMS system. The system automatically aligned the TMS coil to target sites in 3 dimensions with near-perfect coil orientation and real-time head motion correction. Motor maps of 4 forelimb muscles were derived bilaterally by delivering single-pulse TMS at predefined, uniformly spaced trajectories across a 10 × 10 grid (7 mm spacing) customized to the participant's MRI.
RESULTS
Procedures were well tolerated with no adverse events. Two male, eight-year-old participants had high resting motor thresholds that precluded mapping. The mean hotspot coordinate and centre of gravity coordinate were determined in each hemisphere for four forelimb muscles bilaterally. Average mapping time was 14.25 min per hemisphere.
COMPARISON WITH EXISTING METHODS
Traditional manual TMS methods of motor mapping are time intensive, technically challenging, prone to human error, and arduous for use in pediatrics. This novel TMS robot approach facilitates improved efficiency, tolerability, and precision in derived, high-fidelity motor maps.
CONCLUSIONS
Robotic TMS opens new avenues to explore motor map neurophysiology and its influence on developmental plasticity and therapeutic neuromodulation. Our findings provide evidence that TMS robotic motor mapping is feasible in young participants.
Topics: Adolescent; Brain Mapping; Evoked Potentials, Motor; Female; Humans; Male; Motor Cortex; Robotics; Transcranial Magnetic Stimulation
PubMed: 30121208
DOI: 10.1016/j.jneumeth.2018.08.007 -
Neuropsychologia Jul 2018Lesion-behaviour mapping is an influential and popular approach to anatomically localise cognitive brain functions in the human brain. Multiple considerations, ranging... (Review)
Review
Lesion-behaviour mapping is an influential and popular approach to anatomically localise cognitive brain functions in the human brain. Multiple considerations, ranging from patient selection, assessment of lesion location and patient behaviour, spatial normalisation, statistical testing, to the anatomical interpretation of obtained results, are necessary to optimize a lesion-behaviour mapping study and arrive at meaningful conclusions. Here, we provide a hitchhiker's guide, giving practical guidelines and references for each step of the typical lesion-behaviour mapping study pipeline.
Topics: Brain; Brain Injuries; Brain Mapping; Humans
PubMed: 29066325
DOI: 10.1016/j.neuropsychologia.2017.10.021 -
American Journal of Physiologic Imaging 1992Topographic mapping of brain electromagnetic signals has become increasingly popular in recent years both as a clinical tool and as an area of research in its own right.... (Comparative Study)
Comparative Study Review
Topographic mapping of brain electromagnetic signals has become increasingly popular in recent years both as a clinical tool and as an area of research in its own right. The capabilities of existing computerized systems for displaying such maps and for performing localization of current sources in the brain have continued to expand. In this paper we review some of the methodological and technological issues concerning topographic mapping. These include issues of choice of interpolation algorithm, what to map, head geometry, EEG reference location, and scaling. We also discuss characteristics of clinical databases for patient comparison and the usefulness of quantitative EEG (which includes mapping) for the diagnosis of nervous system disorders. Finally, we compare five representative systems in terms of their topographic mapping capabilities. The overall conclusion is that future developments must make use of integrated data from other neuroimaging technologies such as MRI, PET, and SPECT, and determination of the normal limits of topographic parameters must be more carefully examined.
Topics: Brain Mapping; Electroencephalography; Evoked Potentials; Humans; Magnetoencephalography; Technology, Radiologic
PubMed: 1343213
DOI: No ID Found -
Nature Nov 2013
Topics: Animals; Brain; Brain Mapping; Connectome; Humans; Magnetic Resonance Imaging; Mice; Microscopy, Electron, Scanning; Neural Pathways; Neurobiology; Retina
PubMed: 24201287
DOI: 10.1038/503147a -
AJNR. American Journal of Neuroradiology Jun 2014
Topics: Biomarkers; Brain; Brain Diseases; Brain Mapping; Humans; Magnetic Resonance Spectroscopy
PubMed: 24924546
DOI: 10.3174/ajnr.A4020 -
Trends in Cognitive Sciences Sep 2014Brain activity observed at many spatiotemporal scales exhibits a 1/f-like power spectrum, including neuronal membrane potentials, neural field potentials, noninvasive... (Review)
Review
Brain activity observed at many spatiotemporal scales exhibits a 1/f-like power spectrum, including neuronal membrane potentials, neural field potentials, noninvasive electroencephalography (EEG), magnetoencephalography (MEG), and functional magnetic resonance imaging (fMRI) signals. A 1/f-like power spectrum is indicative of arrhythmic brain activity that does not contain a predominant temporal scale (hence, 'scale-free'). This characteristic of scale-free brain activity distinguishes it from brain oscillations. Although scale-free brain activity and brain oscillations coexist, our understanding of the former remains limited. Recent research has shed light on the spatiotemporal organization, functional significance, and potential generative mechanisms of scale-free brain activity, as well as its developmental and clinical relevance. A deeper understanding of this prevalent brain signal should provide new insights into, and analytical tools for, cognitive neuroscience.
Topics: Animals; Brain; Brain Mapping; Brain Waves; Electroencephalography; Humans; Magnetic Resonance Imaging; Magnetoencephalography; Models, Neurological
PubMed: 24788139
DOI: 10.1016/j.tics.2014.04.003 -
Clinical Neurophysiology : Official... Jan 2018A number of investigators have reported that event-related augmentation of high-gamma activity at 70-110 Hz on electrocorticography (ECoG) can localize... (Review)
Review
A number of investigators have reported that event-related augmentation of high-gamma activity at 70-110 Hz on electrocorticography (ECoG) can localize functionally-important brain regions in children and adults who undergo epilepsy surgery. The advantages of ECoG-based language mapping over the gold-standard stimulation include: (i) lack of stimulation-induced seizures, (ii) better sensitivity of localization of language areas in young children, and (iii) shorter patient participant time. Despite its potential utility, ECoG-based language mapping is far less commonly practiced than stimulation mapping. Here, we have provided video presentations to explain, point-by-point, our own hardware setting and time-frequency analysis procedures. We also have provided standardized auditory stimuli, in multiple languages, ready to be used for ECoG-based language mapping. Finally, we discussed the technical aspects of ECoG-based mapping, including its pitfalls, to facilitate appropriate interpretation of the data.
Topics: Brain Mapping; Epilepsy; Evoked Potentials; Gamma Rhythm; Humans; Neurophysiological Monitoring; Preoperative Period; Speech Perception
PubMed: 29190521
DOI: 10.1016/j.clinph.2017.10.018 -
Nature Methods Oct 2016Stable in vivo mapping and modulation of the same neurons and brain circuits over extended periods is critical to both neuroscience and medicine. Current electrical...
Stable in vivo mapping and modulation of the same neurons and brain circuits over extended periods is critical to both neuroscience and medicine. Current electrical implants offer single-neuron spatiotemporal resolution but are limited by such factors as relative shear motion and chronic immune responses during long-term recording. To overcome these limitations, we developed a chronic in vivo recording and stimulation platform based on flexible mesh electronics, and we demonstrated stable multiplexed local field potentials and single-unit recordings in mouse brains for at least 8 months without probe repositioning. Properties of acquired signals suggest robust tracking of the same neurons over this period. This recording and stimulation platform allowed us to evoke stable single-neuron responses to chronic electrical stimulation and to carry out longitudinal studies of brain aging in freely behaving mice. Such advantages could open up future studies in mapping and modulating changes associated with learning, aging and neurodegenerative diseases.
Topics: Action Potentials; Aging; Animals; Behavior, Animal; Brain; Brain Mapping; Electric Stimulation; Male; Mice, Inbred C57BL; Microelectrodes; Neurons; Single-Cell Analysis; Stereotaxic Techniques; Time Factors
PubMed: 27571550
DOI: 10.1038/nmeth.3969 -
Neuron Jul 2018Human neuroimaging research has transitioned from mapping local effects to developing predictive models of mental events that integrate information distributed across... (Review)
Review
Human neuroimaging research has transitioned from mapping local effects to developing predictive models of mental events that integrate information distributed across multiple brain systems. Here we review work demonstrating how multivariate predictive models have been utilized to provide quantitative, falsifiable predictions; establish mappings between brain and mind with larger effects than traditional approaches; and help explain how the brain represents mental constructs and processes. Although there is increasing progress toward the first two of these goals, models are only beginning to address the latter objective. By explicitly identifying gaps in knowledge, research programs can move deliberately and programmatically toward the goal of identifying brain representations underlying mental states and processes.
Topics: Brain; Brain Mapping; Humans; Neuroimaging; Neurons
PubMed: 30048614
DOI: 10.1016/j.neuron.2018.06.009