Cerebellum: Functions, Structure, and Location

The cerebellum, which stands for ‘little brain,’ is a hindbrain structure that controls balance, coordination, movement, and motor skills. It is also thought to be important in processing some types of memory.

The cerebellum’s role is not only in physical coordination but also in the regulation of thought and emotion. It is also one of the few brain regions where adult neurogenesis has been observed (Ponti, Peretto & Bonfanti, 2008).

Did you know? Although the cerebellum only accounts for 10% of the overall brain mass, it contains over half of the brain's nerve cells.

Location

The cerebellum is located at the back of the brain, behind the brainstem, below the temporal and occipital lobes, and beneath the back of the cerebrum.

The cerebellum is also divided into two hemispheres, like the cerebral cortex, joined at the midline by a narrow strip of tissue called the vermis.

Here the wiring works differently. Each cerebellar hemisphere controls the same side of the body: the left hemisphere helps coordinate the left arm and leg, not the right.

This is the opposite of the cerebral cortex, which controls the opposite, or contralateral, side of the body. That is why a stroke confined to one side of the cerebellum causes clumsiness on that same side, not the other.

Cerebellum functions

The cerebellum is essential not only for movement but also for various cognitive processes.

Motor Functions

Traditionally linked to movement, the cerebellum helps:

• Coordinate voluntary movements
• Maintain balance and posture
• Refine motor skills
• Support motor learning and adaptation

It receives sensory input about body position and planned movements, allowing it to fine-tune muscle actions, such as coordinating eye movements, without conscious effort.

For example, when learning to ride a bike, the cerebellum adjusts and automates motor patterns over time.

Motor Learning and Procedural Memory

The cerebellum is also central to motor learning. This is the gradual process by which a clumsy, effortful movement becomes smooth and automatic with practice. This stored know-how is a form of procedural memory, the implicit memory system behind skills like typing or riding a bike.

A single neuron runs this whole circuit. It is the Purkinje cell, a large, flat cell in the cerebellar cortex. It releases the inhibitory neurotransmitter GABA and forms the cortex’s only output route.

Each Purkinje cell receives two types of input. Many parallel fibres carry the current motor and sensory context, while a climbing fibre signals when a movement goes wrong.

When the two arrive together, the active parallel-fibre connections are lastingly weakened, a change called long-term depression. The skill is tuned by its own mistakes. Repeated over many trials, this cancels out the part of the movement that keeps going wrong.

The clearest evidence that the cerebellum stores this kind of memory comes from classic work on classically conditioned eyeblink responses in rabbits.

Aim: To find out whether the cerebellum stores this memory.

Method: Rabbits heard a tone immediately before a puff of air to the eye, which reflexively triggered a blink; after many pairings, they learned to blink to the tone alone. Researchers then made small lesions to the cerebellum’s deep nuclei.

Results: Damage to a specific deep nucleus abolished the learned blink to the tone, while leaving the reflexive blink to the air-puff completely intact.

Conclusion: The memory for this learned response is stored in the cerebellum itself, not merely expressed through it. This made it a landmark case of localising a specific memory to a defined piece of brain tissue (McCormick & Thompson, 1984).

Cognitive Functions

Research now shows the cerebellum also contributes to:

• Attention and executive control
• Language processing
• Spatial and temporal awareness
• Working memory
• Emotional regulation

In fact, much of the cerebellum connects to cerebral networks involved in thinking and emotion, not just motor control (Buckner, 2013).

This cognitive role is not spread evenly. It is concentrated in the cerebellum’s largest region, the cerebrocerebellum, the lateral hemispheres that have expanded the most in human evolution and connect most heavily to the thinking cortex.

Damage to this cognitive territory produces a recognisable pattern: planning and working-memory problems, language difficulties, and blunted or poorly regulated emotion. Researchers call this the cerebellar cognitive affective syndrome (Schmahmann & Sherman, 1998).

Structure

The cerebellum consists of the cerebellar cortex, the thin outer layer of grey matter that holds most of its neurons and does most of its information processing.

Beneath the cortex lies a core of white matter. Buried inside that core are the deep cerebellar nuclei, four paired relay stations named the fastigial, globose, emboliform and dentate nuclei.

These neurons relay the cerebellum’s output to other parts of the brain. The Purkinje cells fine-tune each nucleus. They constantly adjust how strongly it fires, as described above.

Within the cerebellum, there are thought to be three anatomical lobes, which are divided by two fissures (large furrows)– the primary fissure and the posterolateral fissure:

• Anterior lobe (anterior meaning ‘to the front’): Primarily involved in the coordination of limb movements.
• Posterior lobe (posterior meaning ‘to the back’): The largest part and plays a significant role in planning, initiating, and timing movements.
• Flocculonodular lobe: The oldest part of the brain in terms of evolution. This part of the cerebellum is responsible for balance and spatial attention, as well as receiving visual input.

The cerebellum can also be divided into three functional areas:

• Cerebrocerebellum – this is the largest area of the cerebellum, responsible for planning movements and motor learning. It also works to regulate the coordination of muscle activation as well as eye movements.
• Spinocerebellum – this area functions in regulating body movements by allowing for error corrections.
• Vestibulocerebellum – this area is involved in controlling balance and flexes of the eyes.

Connections to other parts of the brain and body

Although the cerebellum is often described as a “little brain,” it functions more like a central hub. It constantly exchanges information with other brain regions to coordinate movement, balance, and even cognition.

Input: Where the cerebellum gets its information

The cerebellum receives input from several key systems:

• Spinal cord – Sends information about body position and movement (proprioception).
• Vestibular system – Informs the cerebellum about head position and balance.
• Cerebral cortex – The motor and premotor areas send motor plans to the cerebellum via the middle cerebellar peduncle, allowing the cerebellum to refine upcoming movements.
• Sensory systems – Visual, auditory, and tactile input help the cerebellum adjust movements in real-time.

Integration: Processing information internally

Once information enters the cerebellum, it’s processed in two key areas:

• Cerebellar cortex – The outer layer where most neurons reside. It processes incoming signals and fine-tunes responses.
• Deep cerebellar nuclei – Including the dentate, emboliform, globose, and fastigial nuclei, these structures act as the cerebellum’s output centers, relaying instructions to other brain areas.

Neurotransmitters like GABA (an inhibitory neurotransmitter) and glutamate (an excitatory one) help regulate cerebellar signaling.

These chemicals are essential for balancing activation and inhibition across motor and cognitive circuits.

Output: Where the cerebellum sends its messages

Once processed, the cerebellum sends output through the superior cerebellar peduncle to the thalamus, which then relays signals to the motor cortex and other cortical areas.

This pathway helps adjust motor execution based on real-time sensory feedback.

The cerebellum also communicates with:

• Brainstem nuclei – To help control posture, eye movements, and reflexes.
• Basal ganglia – Although not directly connected, these two systems interact via shared loops with the cortex and thalamus, working together to initiate and refine movements.
• Prefrontal cortex – Involved in planning, attention, and working memory.
• Limbic system – Plays a role in emotional regulation and motivation, potentially explaining why cerebellar abnormalities are linked to mood disorders.

Related conditions

ADHD

ADHD Adults show structural differences in the middle cerebellar peduncle, particularly reduced white matter organization.

These differences are linked to core symptoms like hyperactivity and inattention, suggesting that the cerebellum may play a role in the cognitive aspects of ADHD (Parkkinen et al., 2024).

This aligns with the cerebellum’s known involvement in attention and working memory, both areas of difficulty in ADHD.

Autism

Cerebellar disruptions, especially involving Purkinje cells, have been linked to autism-like behaviors in animal studies, such as social challenges and repetitive actions.

Abnormal connectivity between the cerebellum and cerebral cortex is also observed in autistic individuals (van der Heijden et al., 2021).

Findings are mixed. A large study of over 400 participants found no consistent anatomical differences in the cerebellum between autistic and non-autistic groups (Laidi et al., 2022). This suggests functional or subtle structural changes may matter more than gross anatomical alterations.

Anxiety Disorders

Studies indicate that the cerebellum may contribute to anxiety-related responses.

Lesions in the cerebellum can reduce avoidance behaviors in animal models (Caulfield & Servatius, 2013). In humans, increased cerebellar activity has been observed in PTSD and generalized anxiety disorder (Abadie et al., 1999; Critchley et al., 2000).

This fits a wider pattern. Reduced cerebellar volume and altered blood flow have also been reported in mood disorders (Phillips et al., 2015). Cerebellar activity is thought to feed into the limbic and autonomic circuits that regulate fear and arousal (Critchley et al., 2000).

Schizophrenia

Neuroimaging studies show reduced cerebellar volume and lower blood flow to the cerebellar cortex in people with schizophrenia. This shows up particularly during tasks involving working memory and attention (Nopoulos et al., 1999; Crespo-Facorro et al., 2007).

Researchers call this cognitive dysmetria. It is the same over- and under-shooting the cerebellum produces in movement, applied instead to thought. On this view, schizophrenia partly reflects a breakdown in the smooth coordination of mental processes that the cerebellum normally provides.

These findings support the cerebellum’s role in cognitive and emotional regulation, extending its relevance beyond motor coordination.

Damage

Cerebellar damage can lead to lasting problems with movement, coordination, and thinking, due to the loss of nerve cells.

Common Symptoms:

• Unsteady walking or balance issues
• Tremors (shaking)
• Slurred speech
• Jerky or inaccurate movements
• Difficulty with memory and concentration

Causes of Cerebellar Damage:

• Alcohol use – Intoxication temporarily affects coordination, while chronic misuse can cause lasting damage.
• Head injury – Especially trauma to the back of the head.
• Neurological conditions – Such as Parkinson’s disease, multiple sclerosis, or stroke.
• Infections or brain tumors – That affect the cerebellum.
• Toxins and medications – Including lead, mercury, or long-term use of benzodiazepines.

Taking steps to protect the brain, such as avoiding substance misuse and preventing falls, can help reduce the risk of cerebellar damage.

Critical Evaluation

The cerebellum’s story is well supported, but a balanced account also weighs where the evidence is thinner.

1. Not just a motor organ, but not a second cortex either: the cerebellum clearly does more than movement, yet its cognitive role looks more like fine-tuning than independent thought.
2. Localisation versus network: assigning one function to “the cerebellum” risks ignoring the loops it forms with the cortex, thalamus, and basal ganglia.
3. Correlational and mixed clinical evidence: much of the human evidence linking the cerebellum to psychiatric conditions is correlational, and findings across studies are often inconsistent.
4. Heavy reliance on animal and single-case work: the cleanest mechanistic evidence comes from animal studies, while key cognitive findings rest on small human patient series.

Beyond a Motor Organ, Not a Second Cortex

Ivry and Keele (1989) found that patients with cerebellar damage struggled to judge which of two tones lasted longer, a task with no movement involved at all. Schmahmann and Sherman (1998) later documented a recurring pattern of executive, language, and emotional problems after cerebellar injury.

These findings rule out a purely motor account. But treating it as a second cortex overstates the case: its cognitive role looks modulatory, smoothing and timing processes computed elsewhere (Buckner, 2013).

The distinction matters: cerebellar activity during a cognitive task shows the structure helps run the task smoothly, not that it originates the thought.

The motor account remains the most secure part of the story, since lesion, stimulation, and imaging evidence there converge and cross-validate each other.

Localisation Versus Network

Neuroscientists have long been tempted to assign a single function to a single brain structure. The cerebellum never actually works alone.

Its motor and cognitive roles run through loops with the cerebral cortex, thalamus, basal ganglia, and brainstem, and a lesion’s effect depends on exactly which loop is interrupted.

For this reason, modern accounts locate function in cortico-cerebellar networks, not in the cerebellum as an isolated box. It is one partner in a wider circuit, not a standalone command centre.

A newer functional atlas confirms this, mapped below.

This matters clinically: the same lesion can produce different symptoms depending on which cortical partner it disrupts. That is why clinicians increasingly describe cerebellar syndromes by the network involved, not just the lobe.

Correlational and Mixed Clinical Evidence

Animal studies have tied disrupted Purkinje cells to autism-like behaviour.

Yet Laidi and colleagues (2022) scanned over 400 people and found no consistent difference in cerebellar anatomy between autistic and non-autistic groups.

This is not an isolated contradiction. Reduced cerebellar volume and blood flow have also been reported in schizophrenia, and altered activity in anxiety and mood disorders, but almost all of this evidence is correlational.

Correlation is not causation. A cerebellar difference might merely accompany a disorder rather than cause it. The animal-versus-human mismatch on autism is a clear warning against treating any single finding as the cerebellar marker for a condition.

The safest reading treats the cerebellum as one node in a distributed network that contributes to these conditions, rather than a single structure that explains any of them.

Heavy Reliance on Animal and Single-Case Work

The cleanest mechanistic evidence for how the cerebellum learns comes from rabbits and rodents, not people. The pivotal human evidence for its cognitive role rests on small patient series (Schmahmann & Sherman, 1998).

Conserved animal circuits may not map cleanly onto human conscious skill, and a handful of patients is a fragile base for sweeping claims about cognition. Neither problem is fatal on its own.

What makes the overall picture credible is convergence: the same conclusions keep emerging across species, methods, and imaging (King et al., 2019), discussed next.

No single demonstration proves the case; the weight of many different kinds of evidence pointing the same way does.

This is the same convergence logic used throughout science: no one study is decisive, but many independent studies pointing the same way are hard to dismiss.

Contemporary Research

Recent work asks a different question: not whether the cerebellum contributes to cognition, but how its territory is organised region by region.

The anchor is King and colleagues (2019).

Aim: To build a data-driven map of the cerebellum’s functional regions, not assume they follow its anatomical folds.

Method: Twenty-four healthy adults were scanned with fMRI. They completed an unusually broad battery of about 47 tasks spanning movement, memory, language, and emotion.

Results: The battery revealed roughly ten distinct functional regions whose boundaries cut across the traditional lobes. Only a minority of the cerebellum was devoted to movement. Large territories were engaged specifically by cognitive tasks instead.

Conclusion: The human cerebellum turns out to be largely non-motor. It is functionally organised into a reproducible map that helps interpret what a given lesion or activation means.

This fits earlier meta-analyses that found a motor-versus-cognitive split between the anterior and posterior lobes (Stoodley & Schmahmann, 2009). Clinicians now use it too. They read cerebellar involvement in ADHD through this network lens (Parkkinen et al., 2024). The cerebellum is now a set of networks, not one uniform structure.

References

Abadie, P., Boulenger, J. P., Benali, K., Barre, L., Zarifian, E., & Baron, J. C. (1999). Relationships between trait and state anxiety and the central benzodiazepine receptor: a PET study. European Journal of Neuroscience, 11 (4), 1470-1478.

Buckner, R. L. (2013). The cerebellum and cognitive function: 25 years of insight from anatomy and neuroimaging. Neuron, 80(3), 807-815.

Caulfield, M. D., & Servatius, R. J. (2013). Focusing on the possible role of the cerebellum in anxiety disorders. New Insights into Anxiety Disorders (Durbano F, Ed.). InTech, Rijeka, HR, 41-70.

Crespo-Facorro, B., Barbadillo, L., Pelayo-Terán, J. M., & Rodríguez-Sánchez, J. M. (2007). Neuropsychological functioning and brain structure in schizophrenia. International Review of Psychiatry, 19 (4), 325-336.

Critchley, H. D., Corfield, D. R., Chandler, M. P., Mathias, C. J., & Dolan, R. J. (2000). Cerebral correlates of autonomic cardiovascular arousal: a functional neuroimaging investigation in humans. The Journal of physiology, 523(1), 259-270.

Gowen, E., & Miall, R. C. (2007). The cerebellum and motor dysfunction in neuropsychiatric disorders. The Cerebellum, 6(3), 268-279.

King, M., Hernandez-Castillo, C. R., Poldrack, R. A., Ivry, R. B., & Diedrichsen, J. (2019). Functional boundaries in the human cerebellum revealed by a multi-domain task battery. Nature Neuroscience, 22(8), 1371-1378. https://doi.org/10.1038/s41593-019-0436-x

Laidi, C., Floris, D. L., Tillmann, J., Elandaloussi, Y., Zabihi, M., Charman, T., … & Simonoff, E. (2022). Cerebellar atypicalities in autism?. Biological psychiatry, 92(8), 674-682.

McCormick, D. A., & Thompson, R. F. (1984). Cerebellum: Essential involvement in the classically conditioned eyelid response. Science, 223(4633), 296-299. https://doi.org/10.1126/science.6701513

Nopoulos, P. C., Ceilley, J. W., Gailis, E. A., & Andreasen, N. C. (1999). An MRI study of cerebellar vermis morphology in patients with schizophrenia: evidence in support of the cognitive dysmetria concept. Biological psychiatry, 46 (5), 703-711.

Parkkinen, S., Radua, J., Andrews, D. S., Murphy, D., Dell’Acqua, F., & Parlatini, V. (2024). Cerebellar network alterations in adult attention-deficit/hyperactivity disorder. Journal of Psychiatry and Neuroscience, 49(4), E233-E241.

Phillips, J. R., Hewedi, D. H., Eissa, A. M., & Moustafa, A. A. (2015). The cerebellum and psychiatric disorders. Frontiers in public health, 3, 66.

Ponti, G., Peretto, P., & Bonfanti, L. (2008). Genesis of neuronal and glial progenitors in the cerebellar cortex of peripuberal and adult rabbits. PLoS One, 3 (6), e2366.

Stoodley, C. J. (2016). The cerebellum and neurodevelopmental disorders. The Cerebellum, 15 (1), 34-37.

Further Information

Kniermin J. Neuroscience online: an electronic textbook for the neurosciences. Chapter 5: Cerebellum. University of Texas Health Science Center at Houston.

Stoodley, C. J. (2016). The cerebellum and neurodevelopmental disorders. The Cerebellum, 15(1), 34-37.

D”Angelo, E. (2019). The cerebellum gets social. Science, 363(6424), 229-229.