Ionic Mechanisms of Neuronal Excitability
Information in the nervous system is transmitted by action potentials,which are transient, all-or-none changes in the voltage across the neuronal membrane. Neurons in different parts of the brain produce different patterns of action potentials. For example, in response to an excitatory synaptic stimulus, some cells fire a single action potential whereas others may fire a burst or cluster of action potentials. Still other cells fire action potentials spontaneously, even in the absence of synaptic input. The characteristics of action potentials produced by any cell depend largely on the properties of ion channels that the cell expresses. These ion channels include voltage-gated channels, calcium-gated channels, and neurotransmitter-gated channels. The research interests of this lab are in examining the biophysical properties of ion channels intrinsic to neurons, with a goal of identifying how the diversity of ion channel families revealed by molecular biological studies may contribute to neuronal specialization.
At present, we are studying neurons of the cerebellum, a part of the brain that is involved in the control of motor behavior. The experiments involve electrophysiological patch-clamp recordings from cerebellar neurons that have been isolated from mouse brain, as well as from neurons in cerebellar preparations in which synaptic connections remain intact. Specifically, we are examining how the ionic currents of neurons of the cerebellar nuclei interact to produce spontaneous action potentials, and how this pattern of firing is modified by inhibitory synaptic input from Purkinje neurons of the cerebellar cortex. Such experimental measurements of currents in specific neuronal classes will be important for the development of accurate computer models of neuronal activity, as well as for cellular-level interpretations of systems-level studies of cerebellar function.