UC San Diego

Somatic excitability plays a key role in the patterning of action potential generation by shaping the integration of synaptic information with recent neuronal activity, however its importance has been neglected in a number of systems. An exception is in spontaneously firing neurons of the vestibular system, where intrinsic excitability is central to adaptive plasticity and diversifies the firing properties of distinct cell types in the medial vestibular nuclei (MVN). Experiments revealed that MVN neurons express sodium currents with similar biophysical properties but exhibit different ratios of potassium currents that likely underlie cell type diversity. Recordings of ionic currents during firing demonstrated that high expression of Ca2+-dependent potassium currents decreases neuronal excitability and limits sodium current availability while Kv3-type potassium currents mediate rapid action potential repolarization and protect sodium current availability at high firing rates, creating a broad spectrum of neuronal firing properties in the MVN