The role of brain oscillations in human spatial and verbal cognition: Evidence from intracranial recordings
The high signal-to-noise ratio of human intracranial recordings provides a unique opportunity to examine brain oscillations with high temporal and spatial precision. We have shown that these oscillations occur predominantly in the theta band (4-8 Hz) and appear to be related to the cognitive demands of both spatial and non-spatial memory tasks (e.g., Kahana et al., 1999; Caplan et al, 2001; Raghavachari et al., 2001). These results mirror an extensive literature of the role of theta in rodent navigation, learning and memory. In this talk I will review our recent findings on the role of theta oscillations in maze learning and in verbal working memory. I will describe mathematical techniques for the assessment of frequency specific oscillatory episodes (Caplan et al., 2000) and for the analysis of phase reset (Rizzuto et al., submitted). Finally, I will present new evidence on the role of gamma oscillations in working memory.