Inhibition is a prevalent mode of activity in the neocortex around awake hippocampal ripples in mice

• Published in: eLife Vol. 12
• Main Authors: Karimi Abadchi, Javad, Rezaei, Zahra, Knöpfel, Thomas, McNaughton, Bruce L, Mohajerani, Majid H
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 16.01.2023; eLife Sciences Publications Ltd; eLife Sciences Publications, Ltd
• Subjects: Activity patterns; Animals; Calcium imaging; Deactivation; Electromyography; Electrophysiology; Experiments; Firing pattern; Firing rate; Glutamate; hippocampal-neocortical interaction; Hippocampus; Hippocampus - physiology; Information processing; Memory; memory consolidation; Mice; Neocortex; Neocortex - physiology; Neuroimaging; Neurons - physiology; Neuroscience; sharp-wave ripple; Sleep; Sleep - physiology; Voltage; voltage/glutamate/calcium imaging; Wakefulness - physiology; mouse; sharp-wave ripple; voltage/glutamate/calcium imaging; hippocampus; memory consolidation; neuroscience; hippocampal-neocortical interaction; neocortex
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.79513

Coordinated peri-ripple activity in the hippocampal-neocortical network is essential for mnemonic information processing in the brain. Hippocampal ripples likely serve different functions in sleep and awake states. Thus, the corresponding neocortical activity patterns may differ in important ways. We addressed this possibility by conducting voltage and glutamate wide-field imaging of the neocortex with concurrent hippocampal electrophysiology in awake mice. Contrary to our previously published sleep results, deactivation and activation were dominant in post-ripple neocortical voltage and glutamate activity, respectively, especially in the agranular retrosplenial cortex (aRSC). Additionally, the spiking activity of aRSC neurons, estimated by two-photon calcium imaging, revealed the existence of two subpopulations of excitatory neurons with opposite peri-ripple modulation patterns: one increases and the other decreases firing rate. These differences in peri-ripple spatiotemporal patterns of neocortical activity in sleep versus awake states might underlie the reported differences in the function of sleep versus awake ripples.