Encoding new spatial information by optogenetically identified mossy and granule cell in the Dentate gyrus

Abstract

The dentate gyrus (DG) is known to be critical for detecting changes in environments, however the specific roles of main excitatory cell types of DG: granule cells (GC) and mossy cells (MC) are still unknown. Here we designed reusable optoelectronic probe for chronic single unit recording and optogenetic manipulations. By implementing optogenetic labeling using this tool, I was able to identify electrophysiological features of GCs and MCs. I observe that fixing a new object, while mice running on the familiar belt, induces a distinct GC and MC response, with maximal alteration near the new object. In general, MCs response is stronger and peaks earlier than GCs. These results suggest that MC spread information about change to GC network thus helping for pattern separation.