B&B Week 9 Flashcards
(198 cards)
what two areas does the basal ganglia communicate with?
there are tracts between the basal ganglia and the thalamus, and the basal ganglia and the cortex
what is the striatum?
caudate and putamen
what is the input to the basal ganglia?
corticostriatal tracts (striatum is caudate plus putamen)
what are the reciprocal interconnections of the basal ganglia?
striato-nigral (between striatum and substantia nigra)
subthalamic nucleus (between STN and globus pallidus)
globus pallidus and striatum
where does the output from the basal ganglia go?
thalamic facsiculus (from globus pallidus to thalamus)–> lenticular fasciculus and ansa lenticularis
what is the major NT of the basal ganglia? what is the clinical correlate for this?
many of the tracts involving the basal ganglia are dopaminergic (i.e nigrostriatal) and thus have implications in psychosis, since psychosis is linked to dopaminergic dysregulation
how many cerebellar hemispheres are there?
2–> there is an ipsilateral and a contralateral side
what is the vermis of the cerebellum?
midline, with nodule as most anterior part
where is the flocculus in the cerebellum?
in the groove between the superior and inferior surfaces
where is the tonsil of the cerebellum?
on the inferior surface –> prominent bulges on hemispheres, adjacent to the vermis
**sit right above the foramen magnum–> can get tonsillar herniation
what are the 3 lobes of the cerebellum?
- flocculonodular
- anterior–> rostral to primary fissure dividing the superior surface in half (quite small compared to posterior lobe)
- posterior–> remainder of the cerebellum
what is the largest cerebellar nucleus? what does it do?
dentate nucleus
links it to the rest of the brain
other than the dentate nucleus, name three other deep cerebellar nuclei
emboliform
globose
fastigial
what neurotransmitter is linked to extra-pyramidal movement disorders?
dopamine deficiency
what are extra-pyramidal symptoms?
include movement disorders –> pseudoparkinsonism, akathisia, akinesia
linked to dopamine deficiency
do NOT involve the pyramidal tract or lateral corticospinal tract
what would lead to extra-pyramidal symptoms? (EPS)
lesions to the cerebellar loops (i.e vestibulocerebellar, spinocerebellar or cerebrocerebellar loops)
what are the two major classifications for the motor system in the brain?
- pyramidal
2. extra-pyramidal
what is the pyramidal portion of the motor system in the brain?
primary motor pathway in the brain, goes via the medullary pyramids
what symptoms does damage to the pyramidal motor system cause?
spasticity (increased tone or passive resistance; velocity and direction dependent)
weakness
paralysis (no movement)
what structures are part of the extra-pyramidal motor system?
contains the basal ganglia structures: caudate and putamen ("striatum") globus pallidus (internal and external) substantia nigra (pars reticularis and pars compacta) subthalamic nucleus
which system is implicated in most movement disorders, extrapyramidal or pyramidal?
extra pyramidal
what symptoms would arise from a lesion in the extrapyramidal pathway?
rigidity
no overt weakness
insufficient OR excessive/abnormal movements (depending on whether the lesion is in the direct or indirect pathways)
what is the direct pathway of the extrapyramidal system?
cortex–> striatum–> GPi/SNr (globus pallidus interna/substantia nigra reticulate)
promotes movement–> “accelerator pedal”
damage to this pathway causes SLOWING of movement
what is the indirect pathway of the extrapyramidal system?
cortex–> striatum–> globus pallidus externa–> subthalamic nucleus–> globus pallidus interna/substantia nigra reticularis
inhibits movement–> “Brake pedal”
damage to this pathway causes EXCESSIVE movement