Enhanced Intrinsic Excitability in Basket Cells Maintains Excitatory-Inhibitory Balance in Hippocampal Circuits
Abstract
Highlights The dynamics of inhibitory circuits is thought to rely on synaptic modifications Results show that basket cells express persistent increase in neuronal excitability This plasticity depends on mGluR5 and involves the regulation of Kv1 channels This plasticity facilitates recruitment of basket cells to balance excitation SUMMARY The dynamics of inhibitory circuits in the cortex is thought to rely mainly on synaptic modifications. We challenge this view by showing that hippocampal parvalbumin-positive basket cells (PV-BCs) of the CA1 region express long-term (>30 min) potentiation of intrinsic neuronal excitability (LTP-IEPV-BC) upon brief repetitive stimulation of the Schaffer collaterals. LTP-IEPV-BC is induced by synaptic activation of metabotropic glutamate receptor subtype 5 (mGluR5) and mediated by the downregulation of Kv1 channel activity. LTP-IEPV-BC promotes spiking activity at the gamma frequency (∼35 Hz) and facilitates recruitment of PV-BCs to balance synaptic and intrinsic excitation in pyramidal neurons. In conclusion, activity-dependent modulation of intrinsic neuronal excitability in PV-BCs maintains excitatory-inhibitory balance and thus plays a major role in the dynamics of hippocampal circuits.
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