Long-term depression of the cerebellar climbing fiber--Purkinje neuron synapse.
In classic Marr-Albus-Ito models of cerebellar function, coactivation of the climbing fiber (CF) synapse, which provides massive, invariant excitation of Purkinje neurons (coding the unconditioned stimulus), together with a graded parallel fiber synaptic array (coding the conditioned stimulus) leads to long-term depression (LTD) of parallel fiber-Purkinje neuron synapses, underlying production of a conditioned response. Here, we show that the supposedly invariant CF synapse can also express LTD. Brief 5 Hz stimulation of the CF resulted in a sustained depression of CF EPSCs that did not spread to neighboring parallel fiber synapses. Like parallel fiber LTD, CF LTD required postsynaptic Ca2+ elevation, activation of group 1 mGluRs, and activation of PKC. CF LTD is potentially relevant for models of cerebellar motor control and learning and the developmental conversion from multiple to single CF innervation of Purkinje neurons.
Hansel
C
C
Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Linden
D J
DJ
D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002531:Cerebellum / Q000502:physiology*; D004558:Electric Stimulation; D004789:Enzyme Activation / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D017774:Long-Term Potentiation / Q000502:physiology*; D009412:Nerve Fibers / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011493:Protein Kinase C / Q000378:metabolism; D011689:Purkinje Cells / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018094:Receptors, Metabotropic Glutamate / Q000502:physiology; D013569:Synapses / Q000502:physiology*
D018094:Receptors, Metabotropic Glutamate; D011493:Protein Kinase C; D002118:Calcium