Flocculus

The flocculus (Latin for "small tuft of wool") is a small lobe of the cerebellum located inferiorly, attached to the inferior cerebellar peduncle by a narrow stalk. It forms part of the vestibulocerebellum, the oldest part of the cerebellum evolutionarily.

The flocculus receives input from the vestibular system and visual areas of the brain. Its primary function is to contribute to the vestibulo-ocular reflex (VOR), which stabilizes gaze during head movements. It also plays a role in the adaptation of the VOR, allowing the VOR to adjust to changes in visual input or motor output. This adaptation is essential for maintaining clear vision during activities like reading or running.

Damage to the flocculus can result in various neurological deficits, including impaired balance, nystagmus (involuntary eye movements), and difficulties with gaze stabilization. These deficits reflect the flocculus's critical role in coordinating eye movements and maintaining equilibrium. The flocculus also has connections to other areas of the cerebellum and brainstem, further implicating it in motor control and coordination.