Journal Article

Perception-related Modulations of Local Field Potential Power and Coherence in Primary Visual Cortex of Awake Monkey during Binocular Rivalry

Alexander Gail, Hans Joerg Brinksmeyer and Reinhard Eckhorn

in Cerebral Cortex

Volume 14, issue 3, pages 300-313
Published in print March 2004 | ISSN: 1047-3211
Published online March 2004 | e-ISSN: 1460-2199 | DOI: https://dx.doi.org/10.1093/cercor/bhg129
Perception-related Modulations of Local Field Potential Power and Coherence in Primary Visual Cortex of Awake Monkey during Binocular Rivalry

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Cortical synchronization at γ-frequencies (35–90 Hz) has been proposed to define the connectedness among the local parts of a perceived visual object. This hypothesis is still under debate. We tested it under conditions of binocular rivalry (BR), where a monkey perceived alternations among conflicting gratings presented singly to each eye at orthogonal orientations. We made multi-channel microelectrode recordings of multi-unit activity (MUA) and local field potentials (LFP) from striate cortex (V1) during BR while the monkey indicated his perception by pushing a lever. We analyzed spectral power and coherence of MUA and LFP over 4–90 Hz. As in previous work, coherence of γ-signals in most pairs of recording locations strongly depended on grating orientation when stimuli were presented congruently in both eyes. With incongruent (rivalrous) stimulation LFP power was often consistently modulated in consonance with the perceptual state. This was not visible in MUA. These perception-related modulations of LFP occurred at low and medium frequencies (<30 Hz), but not at γ-frequencies. Perception-related modulations of LFP coherence were also restricted to the low–medium range. In conclusion, our results do not support the expectation that γ-synchronization in V1 is related to the perceptual state during BR, but instead suggest a perception-related role of synchrony at low and medium frequencies.

Keywords: object coding, synchronization, V1, visual awareness

Journal Article.  11511 words.  Illustrated.

Subjects: Neuroscience

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