Flocculonodular lobe

The flocculonodular lobe (vestibulocerebellum) is one of the lobes of the cerebellum. It is a small lobe consisting of the unpaired midline nodule and the two flocculi: one flocculus on either side of the nodule. The lobe is involved in maintaining posture and balance as well as coordinating head-eye movements.

The lobe is functionally associated with the vestibular system and is therefore also referred to as the vestibulocerebellum. It receives second-order fiber afferents from the vestibular nuclei as well as direct first-order afferents from the vestibular ganglion/nerve (the only region of the cerebellum to do so).

The lobe in turn projects efferents back to the vestibular nuclei which in turn give rise or project to: the lateral vestibulospinal tracts which maintain posture and balance by regulating tone of the axial and proximal limb extensor mucles (i.e. the antigravity muscles); the medial vestibulospinal tracts which regulate the tone of neck muscles; and the medial longitudinal fasciculi which coordinates head-eye movements (vestibuloocular reflex).