The role of oscillations in grid cells’ toroidal topology
Fig 5
Jittering the spikes by 125 ms does not destroy the toroidal topology and leaves the grid scores practically unchanged.
(A) Left. Rate maps of 5 representative grid cells from a population of 149 from module Middle. Barcodes in dimension one (H1) and two (H2) with toroidality
. Long, significant bars are indicated by blue arrows. The ordering of the bars along the y-axis is not meaningful. Right. 3-dimensional UMAP embedding of population activity. The color of each point represents the angle along a chosen axis and it is shown only for visualization. (B) Spike times from three simultaneously recorded grid cells showing synchronous theta modulation on the top. Spike times were jittered by zero-mean Gaussian numbers with standard deviation
ms which removed theta correlation, on the bottom. Note that, as a result of jittering, some spikes went out of the depicted range. (C) Same as (A) but for jittered spike trains, which yield toroidality
, similar to unjittered toroidality. (D) The grid score of each cell in module
for the non-jittered and jittered spike trains was similar;
before jittering and
after jittering.