Bilateral Medial Entorhinal Cortex Silencing Causes Remapping in CA1 Cell Assemblies

The discovery of grid cells in the medial entorhinal cortex (mEC) encouraged investigation of the effect of the mEC on the hippocampus. Large lesions of the entorhinal cortex reduced theta oscillations, decreased the fraction of hippocampal CA1 place cells, and affected various features of place field properties. This study performed combined optogenetic and pharmacogenetic local and upstream inactivation in the hippocampus. To silence the mEC, all types of GABAergic interneurons were infected in C57BL/6 transgenic mice by AAV5-mDlx-ChR2- mCherry virus in one or both hemispheres. The virus evenly infected large populations of interneurons throughout the dorsal and mid parts of the superficial layers of mEC, as well as interneurons within the deep layers. In addition, mice were implanted with 64 or 128 channel silicon probes into CA1. The coordinates used for CA1 implants was either −1.8mm AP, +1.5 mm ML from bregma, or −2.0 AP, +1.7mm ML from bregma. This dataset contains electrophysiology and behavioral data.