CA1 20-40 Hz oscillatory dynamics reflect trial-specific information processing supporting nonspatial sequence memory

Abstract

to N.J.F.; R01 MH102392 and R01 AG053555 to M.A.Y.; T32 NS45540 support for 27 S.G.; and T32 DC010775 support for G.A.E.), and the Whitehall Foundation (award Abstract 33The hippocampus is known to play a critical role in processing information about temporal 34 context. However, it remains unclear how hippocampal oscillations are involved, and how their 35 functional organization is influenced by connectivity gradients. We examined local field potential 36 activity in CA1 as rats performed a complex odor sequence memory task. We find that odor 37 sequence processing epochs were characterized by increased power in the 4-8 Hz and 20-40 38 Hz range, with 20-40 Hz oscillations showing a power gradient increasing toward proximal CA1. 39 Running epochs were characterized by increased power in the 8-12 Hz range and across higher 40 frequency ranges (>24 Hz), with power gradients increasing toward proximal and distal CA1, 41 respectively. Importantly, 20-40 Hz power increased with knowledge of the sequence and 42 carried trial-type-specific information. These results suggest that 20-40 Hz oscillations are 43 associated with trial-specific processing of nonspatial information critical for order memory 44