Induced gamma activity in primary visual cortex is related to luminance and not color contrast: an MEG study


Gamma activity in the visual cortex has been reported in numerous EEG studies of coherent and illusory figures. A dominant theme of many such findings has been that temporal synchronization in the gamma band in response to these identifiable percepts is related to perceptual binding of the common features of the stimulus. In two recent studies using magnetoencephalography (MEG) and the beamformer analysis technique, we have shown that the magnitude of induced gamma activity in visual cortex is dependent upon independent stimulus features such as spatial frequency and contrast. In particular, we showed that induced gamma activity is maximal in response to gratings of 3 cycles per degree (3 cpd) of high luminance contrast. In this work, we set out to examine stimulus contrast further by using isoluminant red/green gratings that possess color but not luminance contrast using the same cohort of subjects. We found no induced gamma activity in V1 or visual cortex in response to the isoluminant gratings in these subjects who had previously shown strong induced gamma activity in V1 for luminance contrast gratings.

Publication DOI:
Divisions: College of Health & Life Sciences > School of Psychology
College of Health & Life Sciences > School of Optometry > Optometry
College of Health & Life Sciences > Clinical and Systems Neuroscience
College of Health & Life Sciences > Aston Institute of Health & Neurodevelopment (AIHN)
College of Health & Life Sciences
College of Health & Life Sciences > School of Optometry > Centre for Vision and Hearing Research
Additional Information: Creative Commons Attribution Non-Commercial No Derivatives License
Uncontrolled Keywords: functional imaging,visual cortex,color vision,magnetoencephalography,beamformer,gamma activity,Ophthalmology,Sensory Systems
Publication ISSN: 1534-7362
Last Modified: 12 Jan 2024 08:04
Date Deposited: 11 Mar 2019 17:48
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
http://www.jour ... g/content/8/7/4 (Publisher URL)
PURE Output Type: Article
Published Date: 2008-05-20
Authors: Adjamian, Peyman
Hadjipapas, Avgis
Barnes, Gareth R.
Hillebrand, Arjan
Holliday, Ian E.

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