cerebellums

The term cerebellums is sometimes used to refer collectively to the pair of cerebellar hemispheres that make up the cerebellum in a given animal or human, though the standard anatomical term is cerebellum. Located at the posterior base of the brain, the cerebellums are part of the hindbrain and play a central role in coordinating movement and maintaining balance and posture. The cerebellums consist of two hemispheres connected by a midline vermis and are folded into folia to increase surface area.

The cerebellar cortex has three cellular layers: molecular, Purkinje, and granule. Purkinje cells are the principal output neurons of the cortex, sending inhibitory signals to the deep cerebellar nuclei, which in turn project to motor and premotor centers in the brainstem and thalamus. Afferent signals reach the cerebellums via the inferior, middle, and superior cerebellar peduncles, conveying information from the spinal cord, vestibular system, and cerebral cortex, among other sources.

Functions extend beyond precise motor control. The cerebellums are essential for smooth, coordinated voluntary movements, balance, and motor learning, including the timing of actions. They also participate in cognitive processes such as attention, language, and executive function through cerebro-cerebellar circuits, with ongoing research into these higher-order roles.

The blood supply to the cerebellums comes from the posterior inferior cerebellar artery, anterior inferior cerebellar artery, and superior cerebellar artery. Clinical relevance includes ataxia, dysmetria, intention tremor, and nystagmus following lesions from stroke, tumors, trauma, or degenerative diseases such as spinocerebellar ataxias. Developmentally, the cerebellums arise from the metencephalon of the hindbrain and involve distinctive neuronal populations and synaptic plasticity mechanisms critical for learning.