The dorsal cochlear nucleus (A) has similar cell-types and circuitry to the cerebellum itself (B). Both circuits have a principal output neuron that receives numerous 'parallel fiber' inputs from granule cells.
Synaptic signalling in cerebellum-like circuits
A fundamental question that must be resolved to understand how the brain functions is how incoming neural signals are integrated into a circuit and transformed into a meaningful output. We focus on the auditory dorsal cochlear nucleus and the cerebellum- areas with similar circuit architecture.
The granule cells and unipolar brush cells of cerebellum-like circuits receive signals from a variety of sensory modalities. The DCN is thought to integrate information about the position of the head and ears to determine the source of acoustic signals and to recognize self-generated sounds. The cerebellum integrates vestibular and visual signals to regulate posture and balance. How the cell-types and circuitry of these areas integrate information from multiple sensory systems is not well understood.
Unipolar Brush Cells
The unipolar brush cell (UBC), is especially important to understand, because it dramatically transforms the signal it receives and directs it to hundreds of local neurons. UBCs have an unusual dendritic "brush" that underlies their fascinating synaptic responses. Their synaptic receptors are exposed to glutamate in a way that is not typical in the brain and by studying them we not only learn how signals are transformed by these cells, but also the basic function of their synaptic receptors.