Research interests
Sensory and cortical information entering the cerebellum is processed and integrated by Purkinje cells, the sole projection neurons of the cerebellar cortex encoding the timing signals that allow for motor coordination. Each Purkinje cell receives convergent inputs from granule cells, subject to modulation by inhibitory interneurons. Classic perspectives of a straightforward functional output of the stereotypical circuitry of the cerebellar cortex have been recently challenged in view of emerging evidence alluding to a more complex interplay within the mossy fiber-granule cell-Purkinje cell pathway shaping the output of Purkinje cells. Presently, we are mapping the spatial patterns of activation within this circuitry, thereby addressing several questions that remain under active debate: 1) Does activity in this pathway propagate in a dispersed or patchy manner?; 2) Do the ascending axon and parallel fiber regions of the granule cells provide differential input to Purkinje cells?; and 3) How do molecular layer inhibitory interneurons between granule cells and Purkinje cells modulate Purkinje cell output? In ongoing experiments, Purkinje cell electrical activity in response to glutamate uncaging in multiple underlying granule cell patches is monitored via single-unit extracellular recording in acute cerebellar slices. This is done with inhibition intact or blocked, and using both sagittal and coronal slice orientations. Both spatial and temporal aspects of the response are analyzed.
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