Which layer of the cerebellar cortex is populated mainly by granule cells?

Which layer of the cerebellar cortex is populated mainly by granule cells?

• A. Granular layer
• B. Purkinje layer
• C. Molecular layer
• D. White matter

Answer: (A)

Granule cells are tiny, numerous excitatory neurons that reside in the granular layer—the innermost layer of the cerebellar cortex, just above the white matter. This layer is densely packed with granule cells, which receive input from mossy fibers. Their axons ascend into the molecular layer as parallel fibers and synapse onto the dendrites of Purkinje cells, helping to propagate cerebellar signals. The Purkinje layer contains the large Purkinje cell bodies, while the molecular layer houses Purkinje dendrites and the parallel fibers; white matter lies deeper and is composed of tracts, not cortical neurons. So, the layer populated mainly by granule cells is the granular layer.

Granule cells are tiny, numerous excitatory neurons that reside in the granular layer—the innermost layer of the cerebellar cortex, just above the white matter. This layer is densely packed with granule cells, which receive input from mossy fibers. Their axons ascend into the molecular layer as parallel fibers and synapse onto the dendrites of Purkinje cells, helping to propagate cerebellar signals. The Purkinje layer contains the large Purkinje cell bodies, while the molecular layer houses Purkinje dendrites and the parallel fibers; white matter lies deeper and is composed of tracts, not cortical neurons. So, the layer populated mainly by granule cells is the granular layer.