Basal Ganglia & Cerebellum Flashcards
What is the major function of the cerebellum?
Co-ordination of movement
What area of the frontal lobe is associated with movement?
Posterior portion
What are the gyri of the cerebellum called?
Folia
What are the 3 lobes of the cerebellum?
- anterior lobe
- posterior lobe
- floccululonodular lobe
What lies between anterior and posterior lobe of cerebellum?
Primary fissure
What part of the flocculonodular lobe sticks out like an ear?
Flocculus
The cerebellum is supra tentorial. True/false?
False - it’s infratentorial
How is the cerebellum attached to the brainstem (mostly the pons)?
3 peduncles - middle cerebellar peduncle is largest, superior and inferior smaller
What is the superior and inferior vermis?
ties around the middle of the cerebellum like a worm
What is the name of the deep grey matter embedded in the middle of the cerebellum?
Deep cerebellar nuclei
What is the order of the following grey matter layers in the cerebellar cortex? Purkinje cell layer, molecular layer, granule cell layer. And which is thinnest layer?
Outer: Molecular layer
Middle: Purkinje cell layer
Inner: Granule cell layer
-Purkinje thinnest
From what 3 structures does info arrive into the cerebellum?
Spinal cord,
Cerebral cortex,
Vestibular apparatus
What 2 receptors does info from the spinal cord to cerebellum come from?
- somatic proprioceptors
- pressure receptors
What is the innermost layer of the CEREBELLAR cortex?
Granule cell layer
What cell layer of cerebellar cortex projects efferent axons?
Purkinje cell layer
What are Purkinje cells?
Neurons in cerebellar cortex that are inhibitory. Have lots of dendrites and send info to cerebellum and are involved in coordination and learning.
How does a patient with a spinocerebellum lesion present and explain why this is?
Disturbance of postural control but preserved limb co-ordination as this comes from pontocerebellum
Describe presentation of patient with unilateral cerebellar hemispheric lesion.
Disturbance of limb co-ordination
What side of the body will cerebellar hemispheric lesions present?
Ipsilateral side of lesion
What effect does alcohol have on cerebellum?
bilateral cerebellar dysfunction - slowed, slurred speech, lack of limb coordination
What are basal ganglia AKA basal nuceli?
5 grey matter masses which work with motor cortex to carry out movements
What are 3 main functions of basal ganglia?
- facilitate purposeful movement
- inhibit unwanted movements
- posture & muscle tone
What are the 5 basal ganglia?
- caudate nucleus
- putamen
- globus pallidus
- subthalamic nucleus
- substantia nigra
What makes up the striatum?
Caudate nucleus and putamen
What makes up the lenticular/lentiform nucleus?
- putamen
- globus pallidus
What makes up the corpus striatum?
- caudate nucleus
- putamen
- globus pallidus
Where is caudate nucleus?
begins on floor of lateral ventricle & follows shape of lateral ventricle to end up in roof of ventricle
What separates the caudate nucleus from the lentiform nucleus?
internal capsule
Where is substantia nigra?
two black lines along the midbrain
What is the role of the dopaminic substantia nigra?
makes excitatory and inhibitory pathways in the brain much more effective (damaged in Parkinsons)
Unilateral lesions of the basal ganglia affect the contralateral side of the body. True/false?
True
What do basal ganglia lesions cause? (2)
changes in muscle tone,
dyskinesias e.g. tremor, chorea, myoclonus
What is the name for a sinusoidal movement?
Tremor
What are chorea?
rapid, asymmetrical movements usually affecting distal limb musculature (writhing)
What are myoclonus?
Muscle jerks
Lesions of the basal ganglia can cause paralysis, sensory loss, loss of power or ataxia. True/false?
False!!
What is the pathology of Parkinsons disease?
Degeneration of dopaminergic neurons of the substantia nigra
3 signs of Parkinsons?
akinesia,
rigidity,
resting tremor
What is the inheritance pattern & pathology of Huntington’s disease?
autosomal dominant disorder,
progressive degeneration of the basal ganglia and cerebral cortex
2 signs of Huntington’s disease?
- chorea
- progressive dementia
What pathway is the subthalamic nucleus involved in?
indirect pathway
What is the difference between direct and indirect pathways in the basal ganglia?
- Direct pathway facilitates movement (enhances wanted movements)
- Indirect pathway inhibits movement
