Precerebellar nuclei

Abstract

The cerebellar cortex receives several inputs from the surrounding nuclei, the precerebellar systems. Two major types of precerebellar systems are known; mossy fi ber (MF) and climbing fi ber (CF) systems. MF neurons are found in several nuclei in the brain stem. Four major nuclei in the hindbrain contain MF neurons; the pontine gray nucleus (PGN), the reticulotegmental nucleus (RTN), the lateral reticular nucleus (LRN) and the external cuneate nucleus (ECN). In addition, MF neurons also reside in the spinal trigeminal nucleus (Sp5) in the hindbrain and Clarke’s column (CC) in the spinal cord. MF neurons extend their glutamatergic projection to granule cells conveying peripheral and cortical information to the cerebellum. In contrast, CF neurons are located mainly in the inferior olive nucleus (ION), which receive inputs from the cerebral cortex, the red nucleus, spinal cord and other brain stem nuclei, and extend their glutamatergic projection to Purkinje cells. Both types of precerebellar neurons also project to neurons in the cerebellar nuclei. It is thought that these precerebellar systems transmit the external and internal information to the cerebellar cortex to modulate cerebellar function, including regulation of animal movement.