August 2012
Volume 12, Issue 9
Free
Vision Sciences Society Annual Meeting Abstract  |   August 2012
Is γ-band activity different in primary visual cortex of awake and anesthetized states
Author Affiliations
  • Dajun Xing
    Center for Neural Science, New York University
  • Yutai Shen
    State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University
  • Samuel Burns
    Center for Neural Science, New York University
  • Chun-I Yeh
    Center for Neural Science, New York University
  • Robert Shapley
    Center for Neural Science, New York University
  • Wu Li
    State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University
Journal of Vision August 2012, Vol.12, 91. doi:10.1167/12.9.91
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Dajun Xing, Yutai Shen, Samuel Burns, Chun-I Yeh, Robert Shapley, Wu Li; Is γ-band activity different in primary visual cortex of awake and anesthetized states. Journal of Vision 2012;12(9):91. doi: 10.1167/12.9.91.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Gamma-band (25-90Hz) activity in the local field potentials (LFPs), EEG and MEG is present throughout the cerebral cortex and has been linked to many cognitive functions and mental disorders. It has been hypothesized that gamma activity, as a clock or stop watch signal, plays important roles in perception, attention and memory, which apparently require consciousness, by synchronizing signals in different cortical regions. However, gamma activity can also be found in the brains of anesthetized animals or even in brain slices, which most people would agree lack consciousness. To understand the role of gamma-band activity, we looked for differences in gamma-band activity generated in different cortical states. We characterized the frequency of the gamma peak and the durations of oscillatory epochs using time-frequency analysis of the LFP recorded in the primary visual cortex (V1) of awake and anesthetized macaques. We found that while the frequency at the peak of gamma activity in awake (~60Hz) was significantly higher than in anesthetized (~40Hz) monkeys, gamma-band bursts were not significantly different in awake and anesthetized – in both states the bursts resembled filtered broad-band noise: brief in time and variable in frequency. Such randomness of gamma dynamics can be explained by a cortical model: a recurrent network driven by Poisson noise. The model accounts for the upwards shift of peak gamma frequency in the awake cortex by a change of network parameters. We conclude that gamma activity in V1 is too random to act as a ‘clock’ or ‘stop watch’ in the perceptual or cognitive functions that have been proposed. Instead gamma band activity may be an epiphenomenon and its function needs to be re-evaluated.

Meeting abstract presented at VSS 2012

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×