Functions of the cerebellum !
- Regulation
- Exam priority: medium
The cerebellum compares the movement that was planned with the one being made and corrects it, so motion is smooth, accurate and well timed.
Updated 2026-11-01
Also called: Cerebellar ataxia, Motor coordination
See it in 3D: Cerebellum · Vermis · Cerebellar peduncles · Cerebellar tonsils · Red nucleus · Pons
What it is
The cerebellum does not start movements; it coordinates them. It receives copies of motor commands from the cortex and feedback from muscles, joints and the vestibular system, compares intention with performance and sends corrections through its deep nuclei to the motor cortex (via the thalamus) and to brainstem motor centres. The only output of its cortex, the Purkinje cell, is inhibitory (GABA). It also drives motor learning and contributes to timing and some cognitive functions.
Regulation
- +Mossy fibres (pontine, spinal, vestibular) → granule cells → parallel fibres: Excite Purkinje cells and deep nuclei with the context of the movement
- +Climbing fibres (inferior olive): Signal errors; their strong Purkinje burst drives motor learning (long-term depression)
- −Purkinje cells (GABA): Inhibit the deep cerebellar and vestibular nuclei, shaping and timing their output
- +Deep nuclei (dentate, interposed, fastigial): Excite the thalamus → motor cortex and brainstem motor centres
- −Basket and stellate cells: Inhibit neighbouring Purkinje cells and sharpen the signal
Functional zones of the cerebellum
| Zone | Main input | Output nucleus | Function | Lesion sign |
|---|---|---|---|---|
| Vestibulocerebellum | Vestibular nuclei and labyrinth | Vestibular nuclei (direct) | Balance, eye movements | Truncal sway, nystagmus |
| Spinocerebellum | Spinocerebellar tracts, motor cortex copies | Fastigial and interposed | Posture, correction of limb movement | Gait ataxia (vermis), limb ataxia |
| Cerebrocerebellum | Pontine nuclei (from the cortex) | Dentate → thalamus → cortex | Planning, timing, skilled sequences | Dysmetria, dysdiadochokinesia, intention tremor |
Clinical notes
- Chronic alcohol use, often with thiamine deficiency, damages the anterior vermis: wide-based, unsteady gait.
- A cerebellar infarct or hemorrhage can swell, compress the fourth ventricle and brainstem and cause hydrocephalus; a neurosurgical emergency.
- Multiple sclerosis plaques in cerebellar pathways: intention tremor, scanning speech and nystagmus.
- The cerebellar tonsils herniate through the foramen magnum with high ICP or in a Chiari malformation.
Test yourself
Think of the answer, then tap the question to see it.
Why does a right cerebellar hemisphere lesion affect the right arm?
The right cerebellum projects through the dentate nucleus and superior peduncle to the left thalamus and motor cortex, whose corticospinal tract crosses back to the right body. Two crossings mean same-side signs.
Why does a cerebellar tremor appear when reaching for a cup and not at rest?
The cerebellum corrects movement as it happens. Without it the arm overshoots and overcorrects, so the oscillation grows near the target (intention tremor); at rest no correction is needed.
Purkinje cells are inhibitory. How can they control a movement?
The deep nuclei fire spontaneously; Purkinje cells release GABA onto them, and changing the pattern of that inhibition shapes and times the excitatory output of the nuclei.
Why does closing the eyes not change balance much in a pure vermis lesion, unlike in dorsal column disease?
The problem is coordination itself, not missing position sense, so vision cannot compensate: the patient is already unsteady with eyes open, and Romberg is usually negative.
See it in 3D
The structures of Durgical's 3D anatomy where it happens.
Related topics
- Motor cortex and the corticospinal tract
- Basal ganglia and movement control
- The vestibular system, tone and posture
- Muscle spindle and Golgi tendon organ
- Somatosensory pathways: dorsal column and anterolateral
Related conditions
- Multiple sclerosis
- Ischaemic stroke
- Intracerebral haemorrhage
- Wernicke encephalopathy (thiamine deficiency)
In Biochemistry
Educational physiology content; not a diagnostic or treatment guide and no substitute for a health professional's advice. Values are approximate references. No doses are given.
Sources: Neuroanatomy, Cerebellum (StatPearls (NCBI Bookshelf), 2023); 16.5 The Coordination and Gait Exams (OpenStax (Rice University), 2022); 13.2 The Central Nervous System (OpenStax (Rice University), 2022); Hall JE. Guyton and Hall Textbook of Medical Physiology, 13th ed. (ch. 57). Reference book used to check facts; its text and figures are not reproduced (Elsevier, 2016).
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Representative model, for educational purposes only.