Gamma oscillations in the hippocampus.

Gamma oscillations are thought to temporally link the activity of distributed cells. We discuss mechanisms of gamma oscillations in the hippocampus and review evidence supporting a functional role for such oscillations in several key hippocampal operations, including cell grouping, dynamic routing, and memory. We propose that memory encoding and retrieval are coordinated by different frequencies of hippocampal gamma oscillations and suggest how transitions between slow and fast gamma may occur.