Figure 3.

Inactivation of SOM Interneurons Did Not Change the Spatial Periodicity or Selectivity of Grid Cells

(A) Expression of hM4D-mCitrine in MEC-SOM interneurons (sagittal sections). Low-magnification image of entire MEC (left); high-magnification images from white frame in left panel (right). mCitrine-expressing cells in green (top), SOM-expressing cells in red (middle), merge of mCitrine and SOM in yellow (bottom). Note co-expression of mCitrine and SOM (yellow, bottom).

(B) Example of grid cell from mouse expressing hM4D-mCitrine in SOM interneurons. Symbols as in Figure 1B.

(C) Cumulative frequency diagrams showing no change in grid score, spatial information, or spatial correlation for rate maps of grid cells after CNO. Symbols as in Figure 1C.

(D) Cumulative frequency diagrams showing significant increase in mean firing rate inside, but not outside, grid fields after inactivation of SOM interneurons.

(E) Cumulative frequency diagrams showing no change of grid scores after inactivation of SOM interneurons. See Figure S4 for absolute scores.

(F) Color-coded rate maps for grid cells from MEC layers II (left) and III (right) after inactivation of SOM interneurons (six layer II and six layer III cells with approximately similar baseline grid scores).

See also Figures S1, S2, S3, S4, and S5.