A new look at gamma? High- (>60 Hz) γ-band activity in cortical networks: Function, mechanisms and impairment

gamma-band oscillations are thought to play a crucial role in information processing in cortical networks. In addition to oscillatory activity between 30 and 60 Hz, current evidence from electro- and magnetoencephalography (EEG/MEG) and local-field potentials (LFPs) has consistently shown oscillations > 60 Hz (high gamma-band) whose function and generating mechanisms are unclear. In the present paper, we summarize data that highlights the importance of high gamma-band activity for cortical computations through establishing correlations between the modulation of oscillations in the 60-200 Hz frequency and specific cognitive functions. Moreover, we will suggest that high gamma-band activity is impaired in neuropsychiatric disorders, such as schizophrenia and epilepsy. In the final part of the paper, we will review physiological mechanisms underlying the generation of high gamma-band oscillations and discuss the functional implications of low vs. high gamma-band activity patterns in cortical networks. (C) 2010 Published by Elsevier Ltd.