Sensory representations in cerebellar granule cells

Cerebellar granule cells are an attractive model system for examining synaptic transmission and temporal integration, because of their small number of excitatory synaptic inputs and electrotonic compactness. Recent in vivo whole-cell recordings have revealed how sensory stimuli are represented by synaptic activity across multiple modalities and cerebellar regions. By monitoring the activity of individual synapses, the reliability of these unitary signals has been quantified, and the complexity of a granule cell's receptive field has been explored at the highest resolution. Here we describe the emerging principles of synaptic sensory representation and their consequences for information processing in the granule cell layer.