Perineuronal nets stabilize the grid cell network

• Published in: Nature communications Vol. 12; no. 1; p. 253
• Main Authors: Christensen, Ane Charlotte, Lensjø, Kristian Kinden, Lepperød, Mikkel Elle, Dragly, Svenn-Arne, Sutterud, Halvard, Blackstad, Jan Sigurd, Fyhn, Marianne, Hafting, Torkel
• Format: Journal Article
• Language: English; Norwegian
• Published: England Nature Publishing Group 11.01.2021; Nature Publishing Group UK; Nature Portfolio
• Subjects: Action Potentials - physiology; Animals; Charged particles; Computer Simulation; Cortex (entorhinal); Cortex (temporal); Entorhinal Cortex - cytology; Extracellular matrix; Firing pattern; Grid Cells - cytology; Hippocampus; Hippocampus - physiology; Male; Memory tasks; Models, Neurological; Nets; Neurons; Neurons - cytology; Perineuronal nets; Rats; Rats, Long-Evans; Representations; Spatial analysis; Spatial discrimination; Spatial memory; Synapses; Theta Rhythm - physiology; Time Factors
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-20241-w

Grid cells are part of a widespread network which supports navigation and spatial memory. Stable grid patterns appear late in development, in concert with extracellular matrix aggregates termed perineuronal nets (PNNs) that condense around inhibitory neurons. It has been suggested that PNNs stabilize synaptic connections and long-term memories, but their role in the grid cell network remains elusive. We show that removal of PNNs leads to lower inhibitory spiking activity, and reduces grid cells' ability to create stable representations of a novel environment. Furthermore, in animals with disrupted PNNs, exposure to a novel arena corrupted the spatiotemporal relationships within grid cell modules, and the stored representations of a familiar arena. Finally, we show that PNN removal in entorhinal cortex distorted spatial representations in downstream hippocampal neurons. Together this work suggests that PNNs provide a key stabilizing element for the grid cell network.