Computational Analysis of PV+ Basket Cell Contribution to Theta Oscillations in Hippocampal CA1 Networks

Background : Parvalbumin-positive (PV+) basket cells are crucial inhibitory interneurons in hippocampal CA1 networks, but their specific contribution to theta oscillations (4-8 Hz) remains incompletely understood. Theta rhythms are fundamental for memory encoding and spatial navigation, making it essential to characterize the role of PV+ basket cells in their generation and maintenance. Methods : We developed a computational model based on realistic hippocampal CA1 network architecture, incorporating 200 neurons (85% pyramidal cells, 6% PV+ basket cells, 9% other interneurons) with physiologically-based firing rates. Local field potentials were simulated across 8 channels for 10 seconds at 1000 Hz sampling rate. We compared network dynamics between control conditions and selective PV+ basket cell silencing using spectral analysis and firing rate statistics. Results : Selective silencing of PV+ basket cells produced a dramatic 90.7% reduction in theta band power, accompanied by significant increases in pyramidal cell firing rates (from 3.0 ± 0.8 Hz to 5.9 ± 1.0 Hz, 97% increase). Other frequency bands showed differential effects: delta power decreased by 87.0%, gamma power decreased by 55.6%, while alpha and beta bands showed compensatory increases of 50% each. Other interneuron populations showed modest decreases in activity (21%), indicating limited compensatory mechanisms insufficient to restore normal theta oscillations. Conclusions : Our results demonstrate that PV+ basket cells are essential for theta oscillation generation and maintenance in hippocampal CA1 networks. These findings have implications for understanding cognitive deficits associated with interneuron dysfunction in neurological and psychiatric disorders.