7. Motor Disorders Flashcards
What does the superior cerebellar peduncles attach the cerebellum to?
Attaches the cerebellum to the midbrain.
What does the middle cerebellar peduncles attach the cerebellum to?
Attaches the cerebellum to the pons.
What does the inferior cerebellar peduncles attach the cerebellum to?
Attaches the cerebellum to the medulla.
Via what structure does the cerebellum communicate with the cortex?
Via the thalamus.
What structure separates the cerebellum from the pons?
The fourth ventricle.
What is the role of the vermis of the cerebellum?
The vermis regulates trunk musculature.
What is the role of the lateral cerebellum hemispheres?
The lateral cerebellar hemispheres regulars distal structures - limbs.
What two symptoms do lesions in the vermis of the cerebellum cause? If the lesion extends, what other symptom can it cause?
Vermis lesions - truncal ataxia and abnormal gait.
Extension of lesions in the vermis - compression of the fourth ventricle leading to hydrocephalus.
What are the 6 symptoms of cerebellar hemisphere lesions?
Dysdiadochokinesis. Ataxia. Nystagmus. Intention tremor. Slurred speech. Hypotonia.
What is the role of basal ganglia?
Motor function - communicates with the cortex and cerebellum to aid with the initiation of movement.
In which basal ganglia are dopaminergic neurones found?
In the substantia nigra pars compacta.
What is the overall net effect of dopamine in the direct and indirect basal ganglia pathways?
Motor cortex stimulation via the thalamus.
What is the pathological cause of Parkinson’s disease, and so what affect does this have on the direct and the indirect basal ganglia pathways?
Degeneration of the substantia nigra, causing dopamine deficiency.
Direct pathway - still stimulatory on the cortex, just less stimulation encourages.
Indirect pathway - now inhibitory on the cortex.
What 4 general symptoms do basal ganglia disorders cause?
Abnormal motor control.
Altered posture.
Affected muscle tone.
Dyskinesia.
What are the 3 cardinal symptoms of Parkinson’s disease? Name 3 other associated symptoms.
Cardinal - bradykinesia, resting tremor and hypotonia.
Other - hypophonia, reduced facial expression, micrographia, dementia and depression.
What pathological changes in the brain occur in Huntington’s disease, and what affect does this have on the indirect pathway?
Loss of GABA neurones.
Indirect pathway switches off, stimulation of the thalamus, and so overstimulation of the cortex, hence can lead to jerking movements.
What is the genetic inheritance of Huntington’s disease?
Autosomal dominant.
Give 3 symptoms of Huntington’s disease
Chorea, dystonia, incoordination, cognitive decline and behavioural difficulties.
Huntington’s disease is associated with cell loss in which basal ganglia structure?
Striatum - made up fo the putamen and caudate nucleus.
What happens pathologically in the brain in hemiballismus, and so what affect does this have on the indirect basal ganglia pathway?
Subthalamic nuclei damaged, so reduced ability to stimulate the globus pallidus interna, and therefore the globus pallidus interna cannot inhibit the thalamus as effectively. The thalamus stimulates the cortex more, leading to inappropriate movements.
What is the main symptom of hemiballismus?
Unilateral abnormal movement
What does hemiballismus often occur secondary to?
Sub-cortical stroke.
