scholarly journals No Evidence for a Role of Spatially Modulated α-Band Activity in Tactile Remapping and Short-Latency, Overt Orienting Behavior

2020 ◽  
Vol 40 (47) ◽  
pp. 9088-9102
Author(s):  
José P. Ossandón ◽  
Peter König ◽  
Tobias Heed
Keyword(s):  
Short Latency ◽  
Orienting Behavior ◽  
Α Band ◽  
Band Activity

scholarly journals Delta band activity contributes to the identification of command following in disorder of consciousness

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gonzalo Rivera-Lillo ◽  
Emmanuel A. Stamatakis ◽  
Tristan A. Bekinschtein ◽  
David K. Menon ◽  
Srivas Chennu
Keyword(s):  
Functional Neuroimaging ◽  
Brain Activity ◽  
Disorder Of Consciousness ◽  
Fine Grained ◽  
Electrical Brain Activity ◽  
Delta Band ◽  
Delta Modulation ◽  
Command Following ◽  
Band Activity

AbstractThe overt or covert ability to follow commands in patients with disorders of consciousness is considered a sign of awareness and has recently been defined as cortically mediated behaviour. Despite its clinical relevance, the brain signatures of the perceptual processing supporting command following have been elusive. This multimodal study investigates the temporal spectral pattern of electrical brain activity to identify features that differentiated healthy controls from patients both able and unable to follow commands. We combined evidence from behavioural assessment, functional neuroimaging during mental imagery and high-density electroencephalography collected during auditory prediction, from 21 patients and 10 controls. We used a penalised regression model to identify command following using features from electroencephalography. We identified seven well-defined spatiotemporal signatures in the delta, theta and alpha bands that together contribute to identify DoC subjects with and without the ability to follow command, and further distinguished these groups of patients from controls. A fine-grained analysis of these seven signatures enabled us to determine that increased delta modulation at the frontal sensors was the main feature in command following patients. In contrast, higher frequency theta and alpha modulations differentiated controls from both groups of patients. Our findings highlight a key role of spatiotemporally specific delta modulation in supporting cortically mediated behaviour including the ability to follow command. However, patients able to follow commands nevertheless have marked differences in brain activity in comparison with healthy volunteers.

Investigating short latency subcortical vestibular projections in humans: what have we learned?

2019 ◽  
Vol 122 (5) ◽  
pp. 2000-2015 ◽  
Author(s):  
James G. Colebatch ◽  
Sally M. Rosengren
Keyword(s):  
Brain Stem ◽  
Physiological Role ◽  
Vestibular Function ◽  
Short Latency ◽  
Vestibular Evoked Myogenic Potentials ◽  
Ocular Vemp ◽  
Motor Unit Firing ◽  
Cervical Vemp ◽  
Noninvasive Assessment

Vestibular evoked myogenic potentials (VEMPs) are now widely used for the noninvasive assessment of vestibular function and diagnosis in humans. This review focuses on the origin, properties, and mechanisms of cervical VEMPs and ocular VEMPs; how these reflexes relate to reports of vestibular projections to brain stem and cervical targets; and the physiological role of (otolithic) cervical and ocular reflexes. The evidence suggests that both VEMPs are likely to represent the effects of excitation of irregularly firing otolith afferents. While the air-conducted cervical VEMP appears to mainly arise from excitation of saccular receptors, the ocular VEMP evoked by bone-conducted stimulation, including impulsive bone-conducted stimuli, mainly arises from utricular afferents. The surface responses are generated by brief changes in motor unit firing. The effects that have been demonstrated are likely to represent otolith-dependent vestibulocollic and vestibulo-ocular reflexes, both linear and torsional. These observations add to previous reports of short latency otolith projections to the target muscles in the neck (sternocleidomastoid and splenius) and extraocular muscles (the inferior oblique). New insights have been provided by the investigation and application of these techniques.

The diagnosis of brain death: role of short latency evoked potentials

1996 ◽  
Vol 98 (5) ◽  
pp. P73
Author(s):  
E. Facco ◽  
F. Baratto ◽  
M. Munari ◽  
A.U. Behr ◽  
A. Lanzillotta ◽  
...  
Keyword(s):  
Brain Death ◽  
Evoked Potentials ◽  
Short Latency

scholarly journals α-Band activity tracks a two-dimensional spotlight of attention during spatial working memory maintenance

2021 ◽  
Vol 125 (3) ◽  
pp. 957-971
Author(s):  
David W. Sutterer ◽  
Sean M. Polyn ◽  
Geoffrey F. Woodman
Keyword(s):  
Working Memory ◽  
Spatial Working Memory ◽  
Two Dimensional ◽  
Substantial Body ◽  
Visual Hemifield ◽  
Angular Coordinates ◽  
Open Question ◽  
Α Band ◽  
Band Activity

A substantial body of work has shown that patterns of EEG α-band activity track the angular coordinates of attended and remembered stimuli around fixation, but whether these patterns track the two-dimensional coordinates of stimuli presented within a visual hemifield remains an open question. Here, we demonstrate that α-band activity tracks the two-dimensional coordinates of remembered stimuli within a hemifield, showing that α-band activity reflects a spotlight of attention focused on locations maintained in working memory.

Gamma-Band Responses to Perturbed Auditory Sequences: Evidence for Synchronization of Perceptual Processes

2005 ◽  
Vol 22 (3) ◽  
pp. 531-547 ◽  
Author(s):  
Theodore P. Zanto ◽  
Edward W. Large ◽  
Armin Fuchs ◽  
J. A. Scott Kelso
Keyword(s):  
Pure Tone ◽  
Gamma Band ◽  
Maximum Power ◽  
Tone Onset ◽  
Temporal Expectancy ◽  
Gamma Band Activity ◽  
Band Activity

We measured modulations of neuroelectric gamma-band activity (GBA) as subjects listened to isochronous pure-tone sequences with embedded temporal perturbations. Perturbations occurred every 6�10 tones, and at the locus of the perturbation, tones occurred early, on time, or late. In the absence of perturbations, induced (non�phase-locked) GBA reached maximum power simultaneously with the occurrence of tone onsets, whereas evoked (phase-locked) GBA peaks were observed after onsets. During late perturbation trials, peaks in induced activity tended to precede tone onsets, and during early perturbation trials, induced peaks followed tone onsets. Induced peaks returned to synchrony after both types of perturbations. Early tones resulted in a marked increase in evoked GBA power at the locus of the perturbation. The latency of evoked GBA relative to tone onset, as well as some other features of the response, depended asymmetrically on the direction of the perturbation. The current results provide evidence for the synchronization of GBA during the perception of auditory rhythms, thus supporting the role of GBA in temporal expectancy.

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