Module 8: Functional Subdivisions of the cerebellum and dysfunctions

what is the most common symptom of cerebellar lesions?

ataxia, which is defined as impaired coordination of muscle recruitment (not due to weakness, ROM limitations, or abnormal tone changes)

what are some other presentations of cerebellar lesions?

decomposition of movement, intention tremors, hypotonia, dysmetria, and dysarthria

what are the three main functional subdivisions of the cerebellum?

spinocerebellum, vestibulocerebellum, cerebrocerebellum

what structures make up the spinocerebellum?

the vermis and the intermediate zone

what are the inputs and outputs of the spinocerebellum?

inputs from spinal cord and about what our body is doing via the spinocerebellar tract, and output to the medial motor pathways (vestibulospinal, recticulospinal, anterior CST)

what is the function of the spinocerebellum?

enables the nervous system to make postural adjustments/fine tune ongoing movements for future motor commands, predominantly involving muscles of trunk/posture and gait

what is the clinical presentation of lesions to the spinocerebellum?

ataxic movements- gait ataxia, intention tremor, dysarthria, dysdiadochokinesia, dymetria, and decompositon of movement

what is dysdiadochokinesia?

the inability to perform rapid, alternating movements

what is decomposition of movement?

the loss of coordination across joints, movements are no longer smooth and joints move separately

what is dysmetria?

the inability to accurately move towards an intended direction

what structure makes up the vestibulocerebellum?

flocculododular lobe- is the functional name for it

what are the inputs and outputs of the vestibulocerebellum?

the major inputs are from the vestibular system and the superior colliculus, the major outputs are to the vestibular nuclei to influence postural control and eye movements (control of the vestibulo-ocular reflex)

what is the function of the vestibulocerebellum?

regulation of balance and equilibrium, integration of visual and vestibular inputs to coordinate motor activity for posture and head and eye movements

how does damage to the vestibulocerebellum present?

see balance deficits and unsteadiness, truncal ataxia, abnormal eye movements (nystagmus- overshooting of the eye), and decrease eye-head coordination

what structures make up the cerebrocerebellum?

the lateral hemispheres of the cerebellum

what are the inputs and outputs of the cerebrocerebellum?

inputs from the cortex that travel through the pontine nuclei, and outputs to the premotor areas and primary motor cortex, and also the red nucleus

what is the function of the cerebrocerebellum?

planning movements and motor learning, coordinates precise, distal voluntary movements, and important for visually guided movements

what is the clinical presentation of damage to the cerebrocerebellum?

see appendicular ataxia (especially in the hands/fingers), dysarthria, and delay of movement initiation