Motor Disorders Flashcards
Where is the cerebellum located?
In the posterior cranial fossa at the back of the brain
How is the cerebellum separated from the occipital and parietal lobes?
By the tenorium cerebelli
How is the cerebellum seperated from the pons?
By the 4th ventricle
Where does the cerebellum have an important role?
In motor control and coordination
What does the cerebellum consist of?
The vermis (midline) and two lateral hemispheres
What is the role of the vermis?
It regulates the trunk musculature
What is the role of the lateral cerebellar hemispheres?
They regulate distal structures, i.e. the limbs
Are tracts ipsilateral or contralateral in the cerebellum?
Ipsilateral
How does the cerebellum communicate with the brainstem?
Via the cerebellar peduncles
What are the names of the cerebellar peduncles?
- Superior
- Middle
- Inferior
What does the superior cerebellar peduncle attach?
The cerebellum to the midbrain
What does the middle cerebellular peduncle attach?
The cerebellum to the pons
What does the inferior cerebellar peduncle attach?
The cerebellum to the medulla (ps I changed this one Mollie, thank me later x)
What can midline lesions of the cerebellum cause?
Truncal ataxia and abnormal gait
What can extension of midline lesions of the cerebellum cause?
- 4th cranial nerve lesions
- Ipsilateral arm tremors
- Compression of the 4th ventricle
- Hydrocephalus
Where do cerebellular hemisphere lesions cause symptoms?
Ipsilaterally
What are the symptoms of cerebellar hemisphere lesions?
- Dysdiadochokinesis
- Ataxia
- Nystagmus
- Intention tremor
- Scanning dysarthria
- Heel-shin test positivity
What is the basal ganglia?
The area of the brain known to be involved in motor function
What are the important structures in the basal ganglia?
- Caudate nucleus
- Lentiform nucleus
- Substantia nigra
What is the lentiform nucleus made up of?
- Putamen
- Globus pallidus externa
- Globus pallidus interna
What is the substantia nigra made up of?
- Pars compacta
- Pars reticularis
What is the function of the basal ganglia?
It stimulates motor activity in the cerebral cortex
What does the output of the basal ganglia travel via?
The thalamus
What kind of neurones are most of those in the striatum?
GABAergic
What is the substantia nigra made up of?
- Pigmented neurones called the pars compacta dorsally
- Ventral strip called the pars reticularis
What kind of neurones are found in the substantia nigra pars compacta?
Dopaminergic
How is the circuiraty of the basal ganglia arranged?
In direct and indirect pathways, to the thalamus
What is the overall net effect of the direct and indirect pathways in the basal ganglia?
Thalamic stimulation of the motor cortex
How can basal ganglia disorders manifest?
- Abnormal motor control
- Altered posture
- Affects muscle tone
- Dyskinesia
What is Parkinsons disease?
A chronic, progressive movement disorder
What is Parkinsons disease characterised by?
Triad of bradykinesia, tremor, and ridigity
What is the pathological process in Parkinsons disease?
Degeneration of the substantia nigra causes deficiency of dopamine
Other than the characteristic triad, what are the features associated with Parkinsons disease?
- Hypophonia
- Reduced facial expression
- Micrographia
- Dementia
- Depression
What is Huntingtons disease?
A progressive neurological disorder
What is the inheritence pattern of Huntingtons disease?
Autosomal dominant
When is the onset of Huntingtons disease?
30-50 years
What are the symptoms of Huntingtons disease?
- Chorea
- Dystonia
- Incoordination
- Cognitive decline
- Behavioural difficulties
What is the pathological process of Huntingtons disease?
Associated with cell loss within the basal ganglia and cortex
