Grid-layout and theta-modulation of layer 2 pyramidal neurons in medial entorhinal cortex.
Little is known about how microcircuits are organized in layer 2 of the medial entorhinal cortex. We visualized principal cell microcircuits and determined cellular theta-rhythmicity in freely moving rats. Non-dentate-projecting, calbindin-positive pyramidal cells bundled dendrites together and formed patches arranged in a hexagonal grid aligned to layer 1 axons, parasubiculum, and cholinergic inputs. Calbindin-negative, dentate-gyrus-projecting stellate cells were distributed across layer 2 but avoided centers of calbindin-positive patches. Cholinergic drive sustained theta-rhythmicity, which was twofold stronger in pyramidal than in stellate neurons. Theta-rhythmicity was cell-type-specific but not distributed as expected from cell-intrinsic properties. Layer 2 divides into a weakly theta-locked stellate cell lattice and spatiotemporally highly organized pyramidal grid. It needs to be assessed how these two distinct principal cell networks contribute to grid cell activity.
Bernstein Center for Computational Neuroscience, Humboldt University of Berlin, Philippstrasse 13 Haus 6, 10115 Berlin, Germany.
Saikat
S
Ray
Robert
R
Naumann
Andrea
A
Burgalossi
Qiusong
Q
Tang
Helene
H
Schmidt
Michael
M
Brecht
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D064026:Calbindins / Q000032:analysis / Q000378:metabolism; D003712:Dendrites / Q000502:physiology; D018891:Dentate Gyrus / Q000502:physiology; D018728:Entorhinal Cortex / Q000166:cytology* / Q000378:metabolism / Q000502:physiology; D005260:Female; D008297:Male; D009415:Nerve Net; D017966:Pyramidal Cells / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure*; D051381:Rats; D017208:Rats, Wistar; D013194:Staining and Labeling; D013826:Theta Rhythm
D064026:Calbindins; D000109:Acetylcholine