title: Beta oscillation dynamics in extrastriate cortex after removal of primary visual cortex.
abstract: The local field potential (LFP) in visual cortex is typically characterized by the following spectral pattern: before the onset of a visual stimulus, low-frequency oscillations (beta, 12-20 Hz) dominate, whereas during the presentation of a stimulus these oscillations diminish and are replaced by fluctuations at higher frequencies (gamma, >30 Hz). The origin of beta oscillations in vivo remains unclear, as is the basis of their suppression during visual stimulation. Here we investigate the contribution of ascending input from primary visual cortex (V1) to beta oscillation dynamics in extrastriate visual area V4 of behaving monkeys. We recorded LFP activity in V4 before and after resecting a portion of V1. After the surgery, the visually induced gamma LFP activity in the lesion projection zone of V4 was markedly reduced, consistent with previously reported spiking responses (Schmid et al., 2013). In the beta LFP range, the lesion had minimal effect on the normal pattern of spontaneous oscillations. However, the lesion led to a surprising and permanent reversal of the normal beta suppression during visual stimulation, with visual stimuli eliciting beta magnitude increases up to 50%, particularly in response to moving stimuli. This reversed beta activity pattern was specific to stimulus locations affected by the V1 lesion. Our results shed light on the mechanisms of beta activity in extrastriate visual cortex: The preserved spontaneous oscillations point to a generation mechanism independent of the geniculostriate pathway, whereas the positive beta responses support the contribution of visual information to V4 via direct thalamo-extrastriate projections.
authors.affiliation: Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, 60528 Frankfurt, Germany.
authors.forename: Joscha T
authors.identifier: http://orcid.org/0000-0001-6233-1866
authors.initials: JT
authors.lastname: Schmiedt
authors.affiliation: Vanderbilt University, Department of Psychology, Nashville, Tennessee 37240.
authors.forename: Alexander
authors.identifier: http://orcid.org/0000-0002-7250-502X
authors.initials: A
authors.lastname: Maier
authors.affiliation: Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, 60528 Frankfurt, Germany, Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 EN Nijmegen, The Netherlands.
authors.forename: Pascal
authors.identifier: http://orcid.org/0000-0002-4270-1468
authors.initials: P
authors.lastname: Fries
authors.affiliation: Laboratory of Neuropsychology, National Institute of Mental Health, Bethesda, Maryland 20892, and.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Saunders
authors.affiliation: Laboratory of Neuropsychology, National Institute of Mental Health, Bethesda, Maryland 20892, and Neurophysiology Imaging Facility, National Institute of Mental Health, National Institute of Neurological Disorders and Stroke, and National Eye Institute, Bethesda, Maryland 20892.
authors.forename: David A
authors.identifier: http://orcid.org/0000-0002-1345-6360
authors.initials: DA
authors.lastname: Leopold
authors.affiliation: Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, 60528 Frankfurt, Germany, michael.schmid@esi-frankfurt.de.
authors.forename: Michael C
authors.identifier: http://orcid.org/0000-0003-1424-130X
authors.initials: MC
authors.lastname: Schmid
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D008253:Macaca mulatta; D010775:Photic Stimulation; D014793:Visual Cortex / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*
keywords: V4; blindsight; cortex; monkey; neurophysiology; oscillation