PT  - JOURNAL ARTICLE
AU  - Dajun Xing
AU  - Yutai Shen
AU  - Samuel Burns
AU  - Chun-I Yeh
AU  - Robert Shapley
AU  - Wu Li
TI  - Stochastic Generation of Gamma-Band Activity in Primary Visual Cortex of Awake and Anesthetized Monkeys
AID  - 10.1523/JNEUROSCI.5644-11.2012
DP  - 2012 Oct 03
TA  - The Journal of Neuroscience
PG  - 13873--13880a
VI  - 32
IP  - 40
4099  - http://www.jneurosci.org/content/32/40/13873.short
4100  - http://www.jneurosci.org/content/32/40/13873.full
SO  - J. Neurosci.2012 Oct 03; 32
AB  - Oscillatory neural activity within the gamma band (25–90 Hz) is generally thought to be able to provide a timing signal for harmonizing neural computations across different brain regions. Using time–frequency analyses of the dynamics of gamma-band activity in the local field potentials recorded from monkey primary visual cortex, we found identical temporal characteristics of gamma activity in both awake and anesthetized brain states, including large variability of peak frequency, brief oscillatory epochs (<100 ms on average), and stochastic statistics of the incidence and duration of oscillatory events. These findings indicate that gamma-band activity is temporally unstructured and is inherently a stochastic signal generated by neural networks. This idea was corroborated further by our neural-network simulations. Our results suggest that gamma-band activity is too random to serve as a clock signal for synchronizing neuronal responses in awake as in anesthetized monkeys. Instead, gamma-band activity is more likely to be filtered neuronal network noise. Its mean frequency changes with global state and is reduced under anesthesia.