Cerebellar Flashcards
Role of the cerebellum
- Multiple roles in motor learning and skill acquisition
- Modifying movements based on learning
- Motor learning and skill acquisition
- Gaze stability
- Postural responses
- Learning
Primary actions of cerebellum
- coordination of voluntary movement
- maintenance of balance and posture
- cognitive function
- motor learning
- comparator
cerebellar coordination of voluntary movement
- Refines control of multiple joints working together
- Coordinate timing and force
cerebellar maintenance of balance and posture
- Postural adjustments
- Comparison of intention with
afferent information- cerebellum alters signals to motor efferents to modify body position
cerebellar cognitive function
- attention
- rhythm of language
cerebellar motor learning
- Trial and error in learning
- Procedural learning- adaptation, fine tuning based on intention and feedback
Cerebellum acting as comparator
- Cerebellum Predicts Movement as Movement Occurs
- Compensates for errors in movement by comparing
intention of movement with performance - This drives adaptation and learning
Gaze stability
Direct Projections from vestibular nuclei to cerebellum allow us to compare head movement to the clarity of visual image, to adjust and modify VOR as necessary
Cerebellum has a role for objects that are….
in motion, at variable speeds, and variable directions
Things to watch for when observing voluntary movements
- Accuracy
- Velocity
- Range
- Direction
- Rhythm
- Speed
- Safety
Postural control
- Compare our movements to
movements of environment and modify responses to intention - Direct projections from sensory systems allow this to happen automatically based on previous experiences
- Short Latency Responses
- Medium Latency Responses
- Long Latency Responses
inputs to cerebellum
- Information into cerebellum from cortex regarding intended movements
- Information from brainstem and spinal cord from sensory receptors regarding actual movement
Anatomical input to superior peduncle
primary motor efferent effect limb movement
anatomical input to middle peduncle
sensory afferent including proprioception, auditory, visual, and somatosensory information
anatomical input to inferior peduncle
afferent tracts of proprioception information, efferents affecting axial muscle activity and postural control
functional anatomy - spinocerebellum
- Output primarily focused on axial and limb musculature
- Produces adaptive motor coordination- error correction
Injury to spino-cerebellum can produce:
- Hypotonia with weakness/ fatigue
- Truncal ataxia
- Static postural tremor and increased postural sway
- Wide BOS, high guard arm position
- Poor anticipatory postural control
- Impaired adaptive motor coordination
- Abnormal balance responses
- Difficulties with automatic gait
- Dyssynergia
Functional anatomy - cerebrocerebellum
- Planning and Timing of Movements
- Cognitive Functions related to Cerebellum/Important in visually guided movements
- Ipsilateral symptoms typical
injury to cerebrocerebellum can result in:
- Impaired coordination- planning/timing of movements * Deficits in motor learning
- Impaired initiation of movement
- Impaired speech patterns
- Multi-segmental movement decomposition (dyssynergia)
- Dysmetria
- Dysdiodochokinesia
- Intention Tremor
Functional Anatomy - Flocculonodular Lobe
- Central vestibular symptoms- poor eye pursuit, VOR,
impaired eye-hand coordination - Gait and trunk ataxia, poor postural control, wide based gait
- Complaints of dizziness/imbalance
- Little change in tone or dyssynergia of extremities
Possible diseases/ lesions to cerebellum
- Hereditary ataxia, Friedreich’s ataxia
- Neoplastic or metastatic tumors
- Infection
- Vascular stroke
- Developmental- ataxia, cerebral palsy, Arnold-Chiari syndrome
- Trauma-TBI
- Drugs, heavy metals
- Chronic alcoholism
Cerebellar Stroke - Anterior Inferior Cerebellar Artery (12%)
- Isolated vestibular syndrome- vertigo, with auditory symptoms such as hearing loss
- Lateral Pontine Syndrome
- Mid-basilar Syndrome
- Hemifacial paralysis, Horner
syndrome, gait and ipsilateral limb ataxia
Cerebellar Stroke - Superior Cerebellar Artery (36%)
- Acute Gait or trunk instability with associated dysarthria, nausea, vomiting
- Lateral midbrain Syndrome
- Top-Basilar Syndrome
- Oculomotor palsy
Cerebellar Stroke - Posterior Inferior Cerebellar Artery (40%)
- Isolated acute vestibular syndrome without auditory symptoms
- Lateral medullary syndrome
- Vertebral artery syndrome
- Leaning ipsilateral to lesion (lateropulsion)