The Journal of Neuroscience, May 23, 2007, 27(21):5672-5682; doi:10.1523/JNEUROSCI.0801-07.2007
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Behavioral/Systems/Cognitive
Impaired Motor Learning in the Vestibulo-Ocular Reflex in Mice with Multiple Climbing Fiber Input to Cerebellar Purkinje Cells
Rhea R. Kimpo and
Jennifer L. Raymond
Department of Neurobiology, Stanford University, Stanford, California 94305-5125
Correspondence should be addressed to Dr. Jennifer L. Raymond, Department of Neurobiology, Stanford University, 299 Campus Drive West, Stanford, CA 94305-5125. Email: jenr{at}stanford.edu
A unique feature of the cerebellar architecture is that Purkinje cells in the cerebellar cortex each receive input from a single climbing fiber. In mice deficient in the 
isoform of protein kinase C (PKC–/– mice), this normal architecture is disrupted so that individual Purkinje cells receive input from multiple climbing fibers. These mice have no other known abnormalities in the cerebellar circuit. Here, we show that PKC–/– mice are profoundly impaired in vestibulo-ocular reflex (VOR) motor learning. The PKC–/– mice exhibited no adaptive increases or decreases in VOR gain at training frequencies of 2 or 0.5 Hz. This impairment was present across a broad range of peak retinal slip speeds during training. We compare the results for VOR motor learning with previous studies of the performance of PKC–/– mice on other cerebellum-dependent learning tasks. Together, the results suggest that single climbing fiber innervation of Purkinje cells is critical for some, but not all, forms of cerebellum-dependent learning, and this may depend on the region of the cerebellum involved, the organization of the relevant neural circuits downstream of the cerebellar cortex, as well as the timing requirements of the learning task.
Key words: climbing fiber; motor learning; cerebellum; vestibulo-ocular reflex; oculomotor; mouse
Received Dec. 7, 2006;
revised April 12, 2007;
accepted April 16, 2007.
Correspondence should be addressed to Dr. Jennifer L. Raymond, Department of Neurobiology, Stanford University, 299 Campus Drive West, Stanford, CA 94305-5125. Email: jenr{at}stanford.edu
