Human gamma-band activity: a window to cognitive processing.

This review highlights recent developments in research on human cortical oscillations in the gamma-band range (30-100 Hz). Electroencephalography has demonstrated a role of these signals for cognitive functions including visual perception, attention, learning and memory. During auditory processing, magnetoencephalogram has identified oscillatory activity in higher frequency ranges and with a more discrete localization than electroencephalogram. Gamma-band activity increases have been observed in the putative auditory dorsal and ventral processing streams during the processing of auditory spatial and pattern information, respectively. Additional gamma-band activity has been found over the frontal cortex during top-down tasks. Oscillatory activity in the gamma range may serve to assess the temporal dynamics of cortical networks and their interactions.