SOMMER, FRIEDRICH T Building analysis tools and a theory framework for inferring principles of neural computation from multi-scale organization in brain recordings EB026955
Abstract 2:
Title: Multiplicative encoding of position and head orientation in multichannel hippocampal LFP
Previous work has shown that hippocampal theta-band local field potentials (LFPs) robustly encode position in rats navigating a linear track. This encoding scheme becomes visibly salient by applying ICA to the multi-channel LFP, producing position-tuned components reminiscent of place fields. However, the position tuning is absent in the ICA output of 64-channel LFP recordings of rats foraging in an open field. This is surprising because simulations of place cell-generated LFP predict place-tuning in both the linear track and open field. We hypothesized that this disparity arises from the fact that position is jointly encoded with the rat’s orientation. We explored this hypothesis by analyzing (1) simulated LFP of rats in the open field, containing multiplicatively encoded position/orientation; (2) 256-channel recordings of CA1 LFP from rats in the open field. The results show that jointly position/orientation-tuned components are gradually resolvable as more channels are added. Our simulations and experimental analyses are captured in a polished and well-documented set of Jupyter notebooks (our “tool”) that may be of broad interest to analysts of electrophysiological data.