Basal ganglia and Cerebellum Flashcards
Where is the primary motor cortex found?
The precentral gyrus in the frontal cortex
What are the 3 lobes of the cerebellum?
Anterior lobe
Posterior lobe
Flocculus
What fissures are present in the cerebellum?
Primary fissure
Horizontal fissure
What is the falx cerebri?
Infolding or dura which does between the great longitudinal fissure
Where does the cerebellum sit in context with the dura?
Posterior cranial fossa under the tentorium cerbelli
How is the cerebellum connected to the brainstem?
Via 3 peduncles of white matter:
Superior, middle and inferior cerebellar peduncle
What is the vermis?
The central zone of the cerebellum
How many deep nuclei are present in the cerebellum and what is the function?
4: only part of the cerebellum that communicates with the brainstem and thalamus
What are the 3 layers to the cerebellum histologically?
Granule (inner)
Purkinje (middle)
Molecular (outer)
What are the afferent projections to the cerebellum?
Spinal cord, from somatic proprioceptors and pressure receptors
Cerebral cortex relayed via the pons
Vestibular apparatus via vestibular nuclei
What are the efference projections of the cerebellum?
All 3 lobes, the only output is via the axons of the purkinje cells which will synapse on neurones of the deep cerebellar nuclei to coordinate all motor tracts
What 3 motor tracts will the cerebellum coordinate?
Corticospinal
Vestibulospinal
Rubrospinal
Where will the neurones go once they have reaches the deep cerebellar nuclei?
Decussate to synapse in the thalamus
Thalamus will then sent fibres to the motor cortex
What results in bilateral cerebellar dysfunction?
Slowed, slurred speech (dysarhria)
Cerebellar ataxia
Which side of the body do cerebellar hemispheres influence?
The ipsilateral side
What will occur in a midline lesion of the cerebellum - spinocerebellum?
Disturbance of postural control
What occurs with a lesion in the vestibulocerebellum?
Vestibular disturbances
What is the functions of the basal ganglia?
Facilitate purposeful movement
Inhibit unwanted movement
Role in posture and muscle tone
What is the basal ganglia made up of?
Caudate nucleus Putamen Globus pallidus Subthalamic nucleus Substantia nigra
What makes up the striatum?
Caudate nucleus
Putamen
What makes up the corpus striatum?
Caudate nucleus
Putamen
Globus pallidus
What makes up the lenticular nucleus?
Putamen
Globus pallidus
Where can the caudate nucleus be found?
Directly inferior to the lateral ventricles
What does the substantia nigra make?
Dopamine
What is the end result of the direct pathway in the basal ganglia?
Enhances outflow of the thalamus, enhancing desired movement
What is the end result of the indirect pathway in the basal ganglia?
Inhibits outflow of the thalamus
Indirectly goes to the subthalamic nucleus
On what side of the body will unilateral lesions of the basal ganglia affect?
Contralateral side of the body
What will lesions of the basal ganglia cause?
Changes in muscle tone Dyskinesias: Tremor Chorea Myoclonus
What is the pathology of parkinson’s disease?
Degeneration of dopaminergic neurones of the substantia nigra
What are the signs of parkinson’s disease?
Akinesia
Rigidity
Resting tremor
What is the pathogenesis of huntington’s disease?
Autosomal dominant progressive degeneration of the basal ganglia and cerebral cortex
What are the signs of huntington’s disease?
Chorea
Progressive dementia
