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Published on: August 14, 2015
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Granular retrosplenial cortex layer 2/3 generates high-frequency oscillations dynamically coupled with hippocampal
Kaiser C Arndt1, Earl T Gilbert1, Lianne M F Klaver1
1School of Neuroscience, Virginia Tech, Blacksburg, VA 24060, USA.
Cell Reports
|March 10, 2024
Summary
High-frequency oscillations (HFOs) in the granular retrosplenial cortex (gRSC) are generated in layer 2/3 and couple with hippocampal rhythms. This suggests a role for gRSC HFOs in interregional communication during distinct brain states.
Area of Science:
- Neuroscience
- Systems Neuroscience
- Computational Neuroscience
Background:
- The granular retrosplenial cortex (gRSC) displays high-frequency oscillations (HFOs) around 150 Hz.
- The hippocampus-subiculum pathway is known to drive these gRSC HFOs.
- The precise cellular-synaptic and laminar mechanisms underlying gRSC HFO generation remain unclear.
Purpose of the Study:
- To investigate the generation of HFOs within the gRSC.
- To examine the coupling of gRSC HFOs with hippocampal rhythms.
- To elucidate the role of gRSC HFOs in interregional communication.
Main Methods:
- Focal optogenetics and silicon-probe recordings were employed in behaving mice.
- CaMKII-expressing cells in different layers (L2/3, L5) of the gRSC were selectively excited.
- Independent component analysis was used to analyze neural activity patterns.
Main Results:
- Optogenetic excitation of CaMKII cells in L2/3 or L5 induced HFOs, but spontaneous HFOs were predominantly observed in L2/3.
- The highest HFO power was localized to the L2/3 of the gRSC.
- gRSC HFOs demonstrated coupling with CA1 sharp wave-ripples (SPW-Rs) during rest and with theta oscillations during specific phases.
- Current source density analysis revealed consistent patterns for HFOs during both SPW-Rs and theta oscillations.
- High gamma oscillations in the CA1 stratum lacunosum moleculare were found to be comodulated with gRSC HFO power.
Conclusions:
- Layer 2/3 of the gRSC is critical for spontaneous HFO generation.
- gRSC HFOs exhibit distinct coupling patterns with hippocampal rhythms (SPW-Rs and theta).
- These findings suggest that gRSC HFOs may facilitate communication within a multisynaptic loop involving the gRSC, hippocampus, and medial entorhinal cortex, potentially supporting distinct brain and behavioral states.
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