Bimodal nonlinear dendrites in PV+ basket cells drive distinct memory-related oscillations

Neuronal oscillations are crucial for organizing distinct memory stages and behavioral states, yet the precise cellular mechanisms through which interneurons shape these dynamics remain incompletely understood. We propose and computationally explore a novel link between the nonlinear dendritic integration modes of parvalbumin-positive fast-spiking basket cells (PV+ FSBCs) and the modulation of hippocampal oscillations. Employing biophysical circuit level modeling, we test the hypothesis that PV+ FSBCs can flexibly adapt their firing patterns and influence rhythms, independent of gross changes in synaptic input quantity, by selectively engaging either their supralinear or sublinear dendritic branches. Specifically, supralinear dendrites promote high-frequency oscillations and reduce the excitation/inhibition (E/I) balance in the circuit, whereas sublinear dendrites enhance slow oscillatory power and elevate the E/I balance. This bimodal dendritic strategy provides PV+ FSBCs with an energy efficient mechanism to regulate circuit and oscillatory dynamics without necessitating large scale increases in synaptic drive. Our findings thereby uncover a previously unrecognized role for PV+ FSBC dendritic computations in regulating memory-related oscillations, offering new, experimentally testable hypotheses into the subcellular mechanisms that govern hippocampal rhythm generation.