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Electrophysiological mapping of the brain

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https://www.readbyqxmd.com/read/29652127/optical-probes-for-neurobiological-sensing-and-imaging
#1
Eric H Kim, Gregory Chin, Guoxin Rong, Kira E Poskanzer, Heather A Clark
Fluorescent nanosensors and molecular probes are next-generation tools for imaging chemical signaling inside and between cells. Electrophysiology has long been considered the gold standard in elucidating neural dynamics with high temporal resolution and precision, particularly on the single-cell level. However, electrode-based techniques face challenges in illuminating the specific chemicals involved in neural cell activation with adequate spatial information. Measuring chemical dynamics is of fundamental importance to better understand synergistic interactions between neurons as well as interactions between neurons and non-neuronal cells...
April 13, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29614077/a-probabilistic-distributed-recursive-mechanism-for-decision-making-in-the-brain
#2
Javier A Caballero, Mark D Humphries, Kevin N Gurney
Decision formation recruits many brain regions, but the procedure they jointly execute is unknown. Here we characterize its essential composition, using as a framework a novel recursive Bayesian algorithm that makes decisions based on spike-trains with the statistics of those in sensory cortex (MT). Using it to simulate the random-dot-motion task, we demonstrate it quantitatively replicates the choice behaviour of monkeys, whilst predicting losses of otherwise usable information from MT. Its architecture maps to the recurrent cortico-basal-ganglia-thalamo-cortical loops, whose components are all implicated in decision-making...
April 2018: PLoS Computational Biology
https://www.readbyqxmd.com/read/29536594/detailed-spatiotemporal-brain-mapping-of-chromatic-vision-combining-high-resolution-vep-with-fmri-and-retinotopy
#3
Sabrina Pitzalis, Francesca Strappini, Alessandro Bultrini, Francesco Di Russo
Neuroimaging studies have identified so far, several color-sensitive visual areas in the human brain, and the temporal dynamics of these activities have been separately investigated using the visual-evoked potentials (VEPs). In the present study, we combined electrophysiological and neuroimaging methods to determine a detailed spatiotemporal profile of chromatic VEP and to localize its neural generators. The accuracy of the present co-registration study was obtained by combining standard fMRI data with retinotopic and motion mapping data at the individual level...
March 13, 2018: Human Brain Mapping
https://www.readbyqxmd.com/read/29529359/tissue-like-neural-probes-for-understanding-and-modulating-the-brain
#4
Guosong Hong, Robert D Viveros, Theodore J Zwang, Xiao Yang, Charles M Lieber
Electrophysiology tools have contributed substantially to understanding brain function, yet the capabilities of conventional electrophysiology probes have remained limited in key ways due to large structural and mechanical mismatches with respect to neural tissue. In this Perspective, we discuss how the general goal of probe design in biochemistry - that the probe or label has a minimal impact on the properties and function of the system being studied - can be realized by minimizing structural, mechanical and topological differences between neural probes and brain tissue, thus leading to a new paradigm of tissue-like mesh electronics...
March 12, 2018: Biochemistry
https://www.readbyqxmd.com/read/29519998/hcn2-rescues-brain-defects-by-enforcing-endogenous-voltage-pre-patterns
#5
Vaibhav P Pai, Alexis Pietak, Valerie Willocq, Bin Ye, Nian-Qing Shi, Michael Levin
Endogenous bioelectrical signaling coordinates cell behaviors toward correct anatomical outcomes. Lack of a model explaining spatialized dynamics of bioelectric states has hindered the understanding of the etiology of some birth defects and the development of predictive interventions. Nicotine, a known neuroteratogen, induces serious defects in brain patterning and learning. Our bio-realistic computational model explains nicotine's effects via the disruption of endogenous bioelectrical gradients and predicts that exogenous HCN2 ion channels would restore the endogenous bioelectric prepatterns necessary for brain patterning...
March 8, 2018: Nature Communications
https://www.readbyqxmd.com/read/29496611/optogenetic-fmri-and-electrophysiological-identification-of-region-specific-connectivity-between-the-cerebellar-cortex-and-forebrain
#6
Katrina Y Choe, Carlos F Sanchez, Neil G Harris, Thomas S Otis, Paul J Mathews
Complex animal behavior is produced by dynamic interactions between discrete regions of the brain. As such, defining functional connections between brain regions is critical in gaining a full understanding of how the brain generates behavior. Evidence suggests that discrete regions of the cerebellar cortex functionally project to the forebrain, mediating long-range communication potentially important in motor and non-motor behaviors. However, the connectivity map remains largely incomplete owing to the challenge of driving both reliable and selective output from the cerebellar cortex, as well as the need for methods to detect region specific activation across the entire forebrain...
February 26, 2018: NeuroImage
https://www.readbyqxmd.com/read/29467145/electrophysiological-signatures-of-spatial-boundaries-in-the-human-subiculum
#7
Sang Ah Lee, Jonathan F Miller, Andrew J Watrous, Michael R Sperling, Ashwini Sharan, Gregory A Worrell, Brent M Berry, Joshua P Aronson, Kathryn A Davis, Robert E Gross, Bradley Lega, Sameer Sheth, Sandhitsu R Das, Joel M Stein, Richard Gorniak, Daniel S Rizzuto, Joshua Jacobs
Environmental boundaries play a crucial role in spatial navigation and memory across a wide range of distantly-related species. In rodents, boundary representations have been identified at the single-cell level in the subiculum and entorhinal cortex of the hippocampal formation. While studies of hippocampal function and spatial behavior suggest that similar representations might exist in humans, boundary-related neural activity has not been identified electrophysiologically in humans until now. To address this gap in the literature, we analyzed intracranial recordings from the hippocampal formation of surgical epilepsy patients (of both sexes) while they performed a virtual spatial navigation task and compared the power in three frequency bands (1-4 Hz, 4-10 Hz, 30-90 Hz) for target locations near and far from the environmental boundaries...
February 21, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/29404403/electrical-stimulation-modulates-high-%C3%AE-activity-and-human-memory-performance
#8
Michal T Kucewicz, Brent M Berry, Vaclav Kremen, Laura R Miller, Fatemeh Khadjevand, Youssef Ezzyat, Joel M Stein, Paul Wanda, Michael R Sperling, Richard Gorniak, Kathryn A Davis, Barbara C Jobst, Robert E Gross, Bradley Lega, S Matt Stead, Daniel S Rizzuto, Michael J Kahana, Gregory A Worrell
Direct electrical stimulation of the brain has emerged as a powerful treatment for multiple neurological diseases, and as a potential technique to enhance human cognition. Despite its application in a range of brain disorders, it remains unclear how stimulation of discrete brain areas affects memory performance and the underlying electrophysiological activities. Here, we investigated the effect of direct electrical stimulation in four brain regions known to support declarative memory: hippocampus (HP), parahippocampal region (PH) neocortex, prefrontal cortex (PF), and lateral temporal cortex (TC)...
January 2018: ENeuro
https://www.readbyqxmd.com/read/29381054/mesh-nanoelectronics-seamless-integration-of-electronics-with-tissues
#9
Xiaochuan Dai, Guosong Hong, Teng Gao, Charles M Lieber
Nanobioelectronics represents a rapidly developing field with broad-ranging opportunities in fundamental biological sciences, biotechnology, and medicine. Despite this potential, seamless integration of electronics has been difficult due to fundamental mismatches, including size and mechanical properties, between the elements of the electronic and living biological systems. In this Account, we discuss the concept, development, key demonstrations, and future opportunities of mesh nanoelectronics as a general paradigm for seamless integration of electronics within synthetic tissues and live animals...
January 30, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29362974/mapping-brain-activity-with-electrocorticography-resolution-properties-and-robustness-of-inverse-solutions
#10
Chiara Todaro, Laura Marzetti, Pedro A Valdés Sosa, Pedro A Valdés-Hernandez, Vittorio Pizzella
Electrocorticography (ECoG) is an electrophysiological technique that records brain activity directly from the cortical surface with high temporal (ms) and spatial (mm) resolution. Its major limitations are in the high invasiveness and in the restricted field-of-view of the electrode grid, which partially covers the cortex. To infer brain activity at locations different from just below the electrodes, it is necessary to solve the electromagnetic inverse problem. Limitations in the performance of source reconstruction algorithms from ECoG have been, to date, only partially addressed in the literature, and a systematic evaluation is still lacking...
January 23, 2018: Brain Topography
https://www.readbyqxmd.com/read/29248603/mixed-metaphors-electrophysiological-brain-responses-to-un-expected-concrete-and-abstract-prepositional-phrases
#11
Emily Zane, Valerie Shafer
Languages around the world use spatial terminology, like prepositions, to describe non-spatial, abstract concepts, including time (e.g., in the moment). The Metaphoric Mapping Theory explains this pattern by positing that a universal human cognitive process underlies it, whereby abstract concepts are conceptualized via the application of concrete, three-dimensional space onto abstract domains. The alternative view is that the use of spatial propositions in abstract phrases is idiomatic, and thus does not trigger metaphoric mapping...
February 1, 2018: Brain Research
https://www.readbyqxmd.com/read/29224723/neural-basis-of-cognitive-control-over-movement-inhibition-human-fmri-and-primate-electrophysiology-evidence
#12
Kitty Z Xu, Brian A Anderson, Erik E Emeric, Anthony W Sali, Veit Stuphorn, Steven Yantis, Susan M Courtney
Executive control involves the ability to flexibly inhibit or change an action when it is contextually inappropriate. Using the complimentary techniques of human fMRI and monkey electrophysiology in a context-dependent stop signal task, we found a functional double dissociation between the right ventrolateral prefrontal cortex (rVLPFC) and the bi-lateral frontal eye field (FEF). Different regions of rVLPFC were associated with context-based signal meaning versus intention to inhibit a response, while FEF activity corresponded to success or failure of the response inhibition regardless of the stimulus response mapping or the context...
December 20, 2017: Neuron
https://www.readbyqxmd.com/read/29219786/periinsular-anterior-quadrantotomy-technical-note
#13
Giulia Cossu, Sebastien Lebon, Margitta Seeck, Etienne Pralong, Mahmoud Messerer, Eliane Roulet-Perez, Roy Thomas Daniel
Refractory frontal lobe epilepsy has been traditionally treated through a frontal lobectomy. A disconnective technique may allow similar seizure outcomes while avoiding the complications associated with large brain resections. The aim of this study was to describe a new technique of selective disconnection of the frontal lobe that can be performed in cases of refractory epilepsy due to epileptogenic foci involving 1 frontal lobe (anterior to the motor cortex), with preservation of motor function. In addition to the description of the technique, an illustrative case is also presented...
February 2018: Journal of Neurosurgery. Pediatrics
https://www.readbyqxmd.com/read/29109247/highly-scalable-multichannel-mesh-electronics-for-stable-chronic-brain-electrophysiology
#14
Tian-Ming Fu, Guosong Hong, Robert D Viveros, Tao Zhou, Charles M Lieber
Implantable electrical probes have led to advances in neuroscience, brain-machine interfaces, and treatment of neurological diseases, yet they remain limited in several key aspects. Ideally, an electrical probe should be capable of recording from large numbers of neurons across multiple local circuits and, importantly, allow stable tracking of the evolution of these neurons over the entire course of study. Silicon probes based on microfabrication can yield large-scale, high-density recording but face challenges of chronic gliosis and instability due to mechanical and structural mismatch with the brain...
November 21, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29078281/multimodal-mapping-of-the-brain-s-functional-connectivity-and-the-adult-outcome-of-attention-deficit-hyperactivity-disorder
#15
Gustavo Sudre, Eszter Szekely, Wendy Sharp, Steven Kasparek, Philip Shaw
We have a limited understanding of why many children with attention deficit hyperactivity disorder do not outgrow the disorder by adulthood. Around 20-30% retain the full syndrome as young adults, and about 50% show partial, rather than complete, remission. Here, to delineate the neurobiology of this variable outcome, we ask if the persistence of childhood symptoms into adulthood impacts on the brain's functional connectivity. We studied 205 participants followed clinically since childhood. In early adulthood, participants underwent magnetoencephalography (MEG) to measure neuronal activity directly and functional MRI (fMRI) to measure hemodynamic activity during a task-free period (the "resting state")...
October 31, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29074287/micromechanical-analysis-of-brain-s-diffuse-axonal-injury
#16
Amir Mohammadipour, Alireza Alemi
Computational models are important tools which help researchers understand traumatic brain injury (TBI). A mechanistic multi-scale numerical approach is introduced to quantify diffuse axonal injury (DAI), the most important mechanism of TBI, induced by a mechanical insult at micro-scale regions of the white matter or voxels where fiber orientations are the same. Using the mechanical properties of a single axon with a viscoelastic constitutive relation and its functional failure in terms of electrophysiological impairment, a numerical 2D micro-level lattice method is implemented to directly analyze the percentage of injured axons in a voxel containing a bundle of axons all with the same orientation under biaxial stretches...
October 9, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/29073650/the-cognitive-map-in-humans-spatial-navigation-and-beyond
#17
REVIEW
Russell A Epstein, Eva Zita Patai, Joshua B Julian, Hugo J Spiers
The 'cognitive map' hypothesis proposes that brain builds a unified representation of the spatial environment to support memory and guide future action. Forty years of electrophysiological research in rodents suggest that cognitive maps are neurally instantiated by place, grid, border and head direction cells in the hippocampal formation and related structures. Here we review recent work that suggests a similar functional organization in the human brain and yields insights into how cognitive maps are used during spatial navigation...
October 26, 2017: Nature Neuroscience
https://www.readbyqxmd.com/read/29070789/the-electrophysiological-connectome-is-maintained-in-healthy-elders-a-power-envelope-correlation-meg-study
#18
N Coquelet, A Mary, P Peigneux, S Goldman, V Wens, X De Tiège
Functional magnetic resonance imaging (fMRI) studies report age-related changes in resting-state functional connectivity (rsFC), suggesting altered or reorganized connectivity patterns with age. However, age-related changes in neurovascular coupling might also partially account for altered connectivity patterns. Here, we used resting-state magnetoencephalography (MEG) and a connectome approach in carefully selected healthy young adults and elders. The MEG connectome was estimated as rsFC matrices involving forty nodes from six major  resting-state networks...
October 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29030110/where-and-what-tms-activates-experiments-and-modeling
#19
Ilkka Laakso, Takenobu Murakami, Akimasa Hirata, Yoshikazu Ugawa
BACKGROUND: Despite recent developments in navigation and modeling techniques, the type and location of the structures that are activated by transcranial magnetic stimulation (TMS) remain unknown. OBJECTIVE: We studied the relationships between electrophysiological measurements and electric fields induced in the brain to locate the TMS activation site. METHODS: The active and resting motor thresholds of the first dorsal interosseous muscle were recorded in 19 subjects (7 female, 12 male, age 22 ± 4 years) using anteromedially oriented monophasic TMS at multiple locations over the left primary motor cortex (M1)...
January 2018: Brain Stimulation
https://www.readbyqxmd.com/read/28990168/automated-analysis-of-seizure-semiology-and-brain-electrical-activity-in-presurgery-evaluation-of-epilepsy-a-focused-survey
#20
REVIEW
David Ahmedt-Aristizabal, Clinton Fookes, Sasha Dionisio, Kien Nguyen, João Paulo S Cunha, Sridha Sridharan
Epilepsy being one of the most prevalent neurological disorders, affecting approximately 50 million people worldwide, and with almost 30-40% of patients experiencing partial epilepsy being nonresponsive to medication, epilepsy surgery is widely accepted as an effective therapeutic option. Presurgical evaluation has advanced significantly using noninvasive techniques based on video monitoring, neuroimaging, and electrophysiological and neuropsychological tests; however, certain clinical settings call for invasive intracranial recordings such as stereoelectroencephalography (SEEG), aiming to accurately map the eloquent brain networks involved during a seizure...
November 2017: Epilepsia
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