scholarly journals The visual gamma response to faces reflects the presence of sensory evidence and not awareness of the stimulus

2016 ◽  
Vol 3 (3) ◽  
pp. 150593 ◽  
Author(s):  
Gavin Perry
Keyword(s):  
Visual Stimuli ◽  
Temporal Cortex ◽  
Gamma Band ◽  
Threshold Condition ◽  
Perceptual Awareness ◽  
Significant Difference ◽  
Sensory Evidence ◽  
Face Stimuli ◽  
Gamma Band Activity ◽  
Band Activity

It has been suggested that gamma (30–100 Hz) oscillations mediate awareness of visual stimuli, but tests of this hypothesis have produced differing results. We used phase scrambling to vary the perceptibility of face stimuli in order to determine whether gamma is indeed linked to perceptual awareness. Magnetoencephalography was used to measure the gamma response in 25 participants while viewing three conditions in which faces were presented either above, below or at the threshold for detection. In each of 400 trials (100 each for the sub- and suprathreshold conditions, 200 for the threshold condition), participants indicated whether they perceived a face in the stimulus. Gamma-band activity during the task was localized to bilateral ventral occipito-temporal cortex. For the threshold condition, we failed to find a significant difference in gamma amplitude between trials in which a face was perceived relative to those in which no face was perceived. However, we did find that gamma amplitude was significantly increased for threshold relative to subthreshold stimuli and for suprathreshold relative to threshold stimuli. This leads us to conclude that the gamma response to faces is primarily modulated by the presence of sensory evidence of a face rather by perceptual awareness.

A quantitative study of gamma-band activity in human intracranial recordings triggered by visual stimuli

2000 ◽  
Vol 12 (7) ◽  
pp. 2608-2622 ◽  
Author(s):  
Jean-Philippe Lachaux ◽  
Eugenio Rodriguez ◽  
Jacques Martinerie ◽  
Claude Adam ◽  
Dominique Hasboun ◽  
...  
Keyword(s):  
Quantitative Study ◽  
Visual Stimuli ◽  
Gamma Band ◽  
Gamma Band Activity ◽  
Intracranial Recordings ◽  
Band Activity

scholarly journals Induced Gamma-Band Activity during Actual and Imaginary Movements: EEG Analysis

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1545
Author(s):  
Carlos Amo Usanos ◽  
Luciano Boquete ◽  
Luis de Santiago ◽  
Rafael Barea Navarro ◽  
Carlo Cavaliere
Keyword(s):  
Brain Activity ◽  
Motor Task ◽  
Gamma Band ◽  
Mean Power ◽  
Significant Difference ◽  
Actual Movement ◽  
The Mean ◽  
The Right ◽  
Gamma Band Activity ◽  
Band Activity

The purpose of this paper is to record and analyze induced gamma-band activity (GBA) (30–60 Hz) in cerebral motor areas during imaginary movement and to compare it quantitatively with activity recorded in the same areas during actual movement using a simplified electroencephalogram (EEG). Brain activity (basal activity, imaginary motor task and actual motor task) is obtained from 12 healthy volunteer subjects using an EEG (Cz channel). GBA is analyzed using the mean power spectral density (PSD) value. Event-related synchronization (ERS) is calculated from the PSD values of the basal GBA (GBAb), the GBA of the imaginary movement (GBAim) and the GBA of the actual movement (GBAac). The mean GBAim and GBAac values for the right and left hands are significantly higher than the GBAb value (p = 0.007). No significant difference is detected between mean GBA values during the imaginary and actual movement (p = 0.242). The mean ERS values for the imaginary movement (ERSimM (%) = 23.52) and for the actual movement (ERSacM = 27.47) do not present any significant difference (p = 0.117). We demonstrated that ERS could provide a useful way of indirectly checking the function of neuronal motor circuits activated by voluntary movement, both imaginary and actual. These results, as a proof of concept, could be applied to physiology studies, brain–computer interfaces, and diagnosis of cognitive or motor pathologies.

Gamma band activity in an auditory oddball paradigm studied with the wavelet transform

2001 ◽  
Vol 112 (7) ◽  
pp. 1219-1228 ◽  
Author(s):  
I.G Gurtubay ◽  
M Alegre ◽  
A Labarga ◽  
A Malanda ◽  
J Iriarte ◽  
...  
Keyword(s):  
Wavelet Transform ◽  
Gamma Band ◽  
Oddball Paradigm ◽  
Auditory Oddball ◽  
Gamma Band Activity ◽  
Auditory Oddball Paradigm ◽  
Band Activity

scholarly journals Increased Thalamic Gamma Band Activity Correlates with Symptom Relief following Deep Brain Stimulation in Humans with Tourette’s Syndrome

PLoS ONE ◽  
2012 ◽  
Vol 7 (9) ◽  
pp. e44215 ◽  
Author(s):  
Nicholas Maling ◽  
Rowshanak Hashemiyoon ◽  
Kelly D. Foote ◽  
Michael S. Okun ◽  
Justin C. Sanchez
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Symptom Relief ◽  
Gamma Band ◽  
Tourette's Syndrome ◽  
Tourette’S Syndrome ◽  
Gamma Band Activity ◽  
Band Activity ◽  
Deep Brain

Gamma band activity and its synchronization reflect the dysfunctional emotional processing in alexithymic persons

2006 ◽  
Vol 43 (6) ◽  
pp. 533-540 ◽  
Author(s):  
Atsushi Matsumoto ◽  
Yoko Ichikawa ◽  
Noriaki Kanayama ◽  
Hideki Ohira ◽  
Tetsuya Iidaka
Keyword(s):  
Emotional Processing ◽  
Gamma Band ◽  
Gamma Band Activity ◽  
Band Activity

scholarly journals Increased EEG gamma band activity in Alzheimer’s disease and mild cognitive impairment

2008 ◽  
Vol 115 (9) ◽  
pp. 1301-1311 ◽  
Author(s):  
J. A. van Deursen ◽  
E. F. P. M. Vuurman ◽  
F. R. J. Verhey ◽  
V. H. J. M. van Kranen-Mastenbroek ◽  
W. J. Riedel
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Gamma Band ◽  
Gamma Band Activity ◽  
Band Activity

Interictal Abnormalities of Gamma Band Activity in Visual Evoked Responses in Migraine: An Indication of Thalamocortical Dysrhythmia?

Cephalalgia ◽  
2007 ◽  
Vol 27 (12) ◽  
pp. 1360-1367 ◽  
Author(s):  
G Coppola ◽  
A Ambrosini ◽  
L Di Clemente ◽  
D Magis ◽  
A Fumal ◽  
...  
Keyword(s):  
High Frequency ◽  
Gamma Band ◽  
Pattern Reversal ◽  
Evoked Responses ◽  
Visual Evoked Responses ◽  
High Frequency Oscillations ◽  
Thalamocortical Dysrhythmia ◽  
Gamma Band Activity ◽  
Band Activity ◽  
Visual Evoked

Between attacks, migraineurs lack habituation in standard visual evoked potentials (VEPs). Visual stimuli also evoke high-frequency oscillations in the gamma band range (GBOs, 20–35 Hz) assumed to be generated both at subcortical (early GBOs) and cortical levels (late GBOs). The consecutive peaks of GBOs were analysed regarding amplitude and habituation in six successive blocks of 100 averaged pattern reversal (PR)-VEPs in healthy volunteers and interictally in migraine with (MA) or without aura patients. Amplitude of the two early GBO components in the first PR-VEP block was significantly increased in MA patients. There was a significant habituation deficit of the late GBO peaks in migraineurs. The increased amplitude of early GBOs could be related to the increased interictal visual discomfort reported by patients. We hypothesize that the hypo-functioning serotonergic pathways may cause, in line with the thalamocortical dysrhythmia theory, a functional disconnection of the thalamus leading to decreased intracortical lateral inhibition, which can induce dishabituation.

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