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Oscillatory Hierarchy Controlling Cortical Excitability and Stimulus IntegrationCortical gamma band oscillations have been recorded in sensory cortices of cats and monkeys, and are thought to aid in perceptual binding. Gamma activity has also been recorded in the rat hippocampus and entorhinal cortex, where it has been shown, that field gamma power is modulated at theta frequency. Since the power of gamma activity in the sensory cortices is not constant (gamma-bursts). we decided to examine the relationship between gamma power and the phase of low frequency oscillation in the auditory cortex of the awake macaque. Macaque monkeys were surgically prepared for chronic awake electrophysiological recording. During the time of the experiments. linear array multielectrodes were inserted in area AI to obtain laminar current source density (CSD) and multiunit activity profiles. Instantaneous theta and gamma power and phase was extracted by applying the Morlet wavelet transformation to the CSD. Gamma power was averaged for every 1 degree of low frequency oscillations to calculate power-phase relation. Both gamma and theta-delta power are largest in the supragranular layers. Power modulation of gamma activity is phase locked to spontaneous, as well as stimulus-related local theta and delta field oscillations. Our analysis also revealed that the power of theta oscillations is always largest at a certain phase of delta oscillation. Auditory stimuli produce evoked responses in the theta band (Le., there is pre- to post-stimulus addition of theta power), but there is also indication that stimuli may cause partial phase re-setting of spontaneous delta (and thus also theta and gamma) oscillations. We also show that spontaneous oscillations might play a role in the processing of incoming sensory signals by 'preparing' the cortex.
Document ID
20050082144
Document Type
Preprint (Draft being sent to journal)
Authors
Shah, A. S. (Kline (Nathan S.) Inst. for Psychiatric Research Orangeburg, NY, United States)
Lakatos, P. (Hungarian Academy of Sciences Budapest, Hungary)
McGinnis, T. (Kline (Nathan S.) Inst. for Psychiatric Research Orangeburg, NY, United States)
O'Connell, N. (Kline (Nathan S.) Inst. for Psychiatric Research Orangeburg, NY, United States)
Mills, A. (Kline (Nathan S.) Inst. for Psychiatric Research Orangeburg, NY, United States)
Knuth, K. H. (NASA Ames Research Center Moffett Field, CA, United States)
Chen, C. (Kline (Nathan S.) Inst. for Psychiatric Research Orangeburg, NY, United States)
Karmos, G. (Hungarian Academy of Sciences Budapest, Hungary)
Schroeder, C. E. (NKI Oraneburg, SC, United States)
Date Acquired
August 22, 2013
Publication Date
January 1, 2004
Subject Category
Life Sciences (General)
Meeting Information
Society for Neuroscience Annual Meeting 2004(San Diego, CA)
Distribution Limits
Public
Copyright
Public Use Permitted.
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