Plasticity of Transporters, Metabotropic Receptors and Voltage-Gated Ion Channels: Things Your Mother Never Told You About Use-Dependent Modulation In The Cerebellum
David J. Linden
Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore , MD , USA
Most models of learning in the cerebellum, and indeed in many brain regions, have assumed that the fundamental cellular mechanism of information storage is the long-term use dependent modulation (LTP/LTD) of fast glutamatergic synaptic transmission. While these phenomena are undoubtedly important, they are one of many electrophysiological functions that can be persistently modified by experience. Here, I will describe recent work from our group on three additional plastic phenomena in cerebellum. First, is a long-term upregulation of neuronal glutamate transporter function in Purkinje cells evoked by repeated climbing fiber stimulation. Second, is a persistent and profound depression of the metabotropic glutamate receptor mGluR1 triggered by Purkinje cell depolarization. Third, is a use-dependent increase in the intrinsic excitability of cerebellar deep nuclear neurons evoked by burst stimulation of either mossy fiber or Purkinje cell axons. It is my hope to stimulate discussion about how these additional forms of plasticity might function in cerebellar circuits and behavior.