Cerebellar Granule Cell

Abstract

The cerebellar granule cells are the most numerous neurons of the brain. They are also among those with the simplest structure by emitting just four short unbranched dendrites innervated by the mossy fibers and a thin axon that branches into the parallel fibers. The granule cells are the only excitatory neurons of the cerebellum (apart of the recently discovered unipolar brush cells (UBCs)) and receive inhibition uniquely through the Golgi cells. Since their early discovery by Camillo Golgi and Ramon y Cajal at the end of the nineteenth century, the granule cells have been the object of intensive investigation. The milestones have been the field recording of their activity in the 1960s, the discovery of their GABAergic inhibition in the 1970s and of their glutamatergic excitation in the 1980s, and the characterization of their membrane and synaptic mechanisms with patch-clamp techniques in the 1990s. Then in the last two decades, a series of

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“…The cell responsible for the massive neuronal density of the cerebellum is the cerebellar granule cell, which accounts for nearly 75% of the total number of neurons in the mammalian nervous system ( 36 ). Granule cells receive cortical input from ponto-cerebellar mossy fibers via glutamatergic neurotransmission and project, via parallel fibers, output to Purkinje cells ( 36 , 37 ). The Purkinje cells then receive excitatory inputs from both granule cell/parallel fiber inputs and olivary projections via climbing fibers ( 36 , 37 ).…”

“…Granule cells receive cortical input from ponto-cerebellar mossy fibers via glutamatergic neurotransmission and project, via parallel fibers, output to Purkinje cells ( 36 , 37 ). The Purkinje cells then receive excitatory inputs from both granule cell/parallel fiber inputs and olivary projections via climbing fibers ( 36 , 37 ). This afferent input to the Purkinje cell, which includes pan-cortical input from the ponto-cerebellar projection and peripheral nervous system input from the spino-olivary projection, has been described as “the system with the largest information bandwidth” in the central nervous system ( 38 , 39 ).…”

“…This afferent input to the Purkinje cell, which includes pan-cortical input from the ponto-cerebellar projection and peripheral nervous system input from the spino-olivary projection, has been described as “the system with the largest information bandwidth” in the central nervous system ( 38 , 39 ). Central to this informational throughput is AMPAr-mediated neurotransmission, which is involved in the mediation of each synapse of the afferent projection system: the ponto-cerebellar mossy fiber to granule cell synapse, the olivo-cerebellar climbing fiber to Purkinje cell synapse, and the cerebellar cortical parallel fiber to Purkinje cell synapse ( 36 , 37 , 40 ).…”