title: Speed controls the amplitude and timing of the hippocampal gamma rhythm.
abstract: Cortical and hippocampal gamma oscillations have been implicated in many behavioral tasks. The hippocampus is required for spatial navigation where animals run at varying speeds. Hence we tested the hypothesis that the gamma rhythm could encode the running speed of mice. We found that the amplitude of slow (20-45 Hz) and fast (45-120 Hz) gamma rhythms in the hippocampal local field potential (LFP) increased with running speed. The speed-dependence of gamma amplitude was restricted to a narrow range of theta phases where gamma amplitude was maximal, called the preferred theta phase of gamma. The preferred phase of slow gamma precessed to lower values with increasing running speed. While maximal fast and slow gamma occurred at coincident phases of theta at low speeds, they became progressively more theta-phase separated with increasing speed. These results demonstrate a novel influence of speed on the amplitude and timing of the hippocampal gamma rhythm which could contribute to learning of temporal sequences and navigation.
authors: Department of Physics and Astronomy, and Integrative Center for Learning and Memory, University of California at Los Angeles, Los Angeles, California, United States of America.
authors: Zhiping
authors: Z
authors: Chen
authors: Evgeny
authors: E
authors: Resnik
authors: James M
authors: JM
authors: McFarland
authors: Bert
authors: B
authors: Sakmann
authors: Mayank R
authors: MR
authors: Mehta
mesh_terms: D000818:Animals; D058256:Brain Waves / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012420:Running / Q000502:physiology; D013826:Theta Rhythm / Q000502:physiology; D013997:Time Factors