Neuro (03.27) Basal Ganglia Flashcards
the basal ganglia refers to structures that yield distinctive kinds of ___ ___ when damaged
movement disorders
what are the 4 main components of the basal ganglia?
- striatum
- globus pallidus
- subthalamic nucleus
- substantia nigra
what are the three parts of the striatum?
- caudate nucleus
- nucleus accumbens
- putamen
what are the two parts of the globus pallidus ?
- external segment
- internal segment
what does the lenticular nucleus comprise?
- all of globus pallidus
- putamen (of striatum)
what are the two parts of the substantia nigra
- compact part
- reticular part
c-shaped part of the basal ganglia that is the LATERAL wall of the third ventricle and has a head, body, and tail
caudate
the ____ ___ has extensive basil ganglia output to thalamus
globus pallidus
regarding the basil ganglia, what are the three hyperkinetic disorders that involve involuntary movement
- chorea
- athetosis
- ballismus
occurs in hyperkinetic disorders where tone increases in some mm causing the body to be bent/twisted into abnormal, fixed posture
dystonia
what is the disease that is associated with dystonia
parkinson’s disease
the compact part of the substantia nigra provides diffuse, modulatory _____ projections to ____
- dopaminergic
- striatum
the _____ part of the substantia nigra is pigmented
compact
the reticular part of the substantia nigra is closer to the ____ ____ than the compact part and is a basal ganglia ____ ____
- cerebral peduncle
- output nucleus
regarding the basal ganglia, motor control is mediated by interactions with the ___ ___ and other structures
motor cortex
what are the four functions of the basal ganglia?
- cognition
- motor
- emotion
- motivation
regarding the basal ganglia connectivity, the inputs are ___ afferents going to ____ and ____
- cortical
- striatum
- subthalamus
regarding the basal ganglia connectivity, what are the two outputs?
- globus pallidus interna
- substantia nigra reticular
regarding the basal ganglia connectivity, excitatory connections (corticostriate, thalamocortical) use ____
glutamate
regarding the basal ganglia connectivity, inhibitory connections (globus pallidus interna and substantia nigra reticular) use _____
GABA
the basal ganglia (can/cannot) influence motor cortex directly
cannot
the basal ganglia role in motor control is to influence ____ ____ pathway by affecting activity in ____ motor areas
- descending motor
- cortical
describe the basal ganglia loop in which the basal ganglia influences descending motor pathways
somatosensory & motor cortex ->
striatum -> globus pallidus interna ->
VA/VL in thalamus -> back to top
the striatum looks uniform in routinely stained sections, but special stains show that it is divided into what two things?
- discrete patches (striosomes)
- matrix territories
in the direct pathway, what fibers are excitatory?
- corticostriate fibers to striatum
- thalamus that activates the cotex
- output from the cortex
in the direct pathway, what fibers are inhibitory?
- fibers from striatum to globus pallidus interna
3. fibers from globus pallidus interna to thalamus
degeneration of striatum (more caudate than putamen)
huntington’s disease (chorea)
when is huntington’s disease most likely to happen to ppl?
age 50
what are the symptoms of huntington’s disease?
rapid movements of face and limbs
looks like a dance
(chorea)
*movements resemble normal voluntary movements and are rather rhythmic
what are the 7 steps of a normal indirect pathway?
- cortical input
- striatal output
- DEC globus pallidus externa output
4/5. increase thalamic inhibition - DEC output to cortex
- DEC cortical output to limbs
what happens to the indirect pathway if there is a damaged sub thalamus?
disinhibits thalamus which results in failure to suppress cortical outputs and leads to hemiballismus (involuntary movements)
dramatic movement disorder that involves flailing and rotary limbs
hemiballismus
hemiballismus affects both sides of the body (T/F)
false
*may affect arm and leg to different degrees
hemiballismus is usually in ___ patients and is due to a cerebrovascular accident (stroke) in the branch of ____ ____ artery
- older
- posterior cerebral artery
regarding inputs and outputs, which part of the substantia nigra is similar to that of globus pallidus interna?
substantia nigra reticular
what two things are the main outputs from the basal ganglia?
- substantia nigra reticular
- globus pallidus interna
for a patient to be considered to have parkinson’s disease, they must have two of three cardinal features including:
- bradykinesia
- resting tremor
- rigidity
what is the age of onset for parkinson’s disease?
60
concerning parkinson’s disease, the substantia nigra compact part neurons contain ___ ____
lewy bodies
biologically and anatomically, explain how parkinson’s disease works
decrease in dopamine leads to less outputs from substantia nigra to striatum. that leads to more inhibition from sub thalamus to globus pallidus interna which leads to more inhibition of thalamus which leads to hypokinesia and bradykinesia
the idea to treat parkinson’s disease is to replace _____ lost due to degeneration of ____ fibers using ____. the response is helpful but can fluctuate over time and can induce ____ _____
- dopamine
- nigrostriatal fibers
- levodopa
- involuntary movement
why is the treatment of parkinson’s disease by means of pallidotomy risky?
VA/VL and globus pallidus interna are deep in the brain and near internal capsule so that could be accidentally cut
pallidotomy would reduce parkinson’s disease symptoms in the limb _____ to the pallidotomy
contralateral
___ ____ therapy can also be used to treat parkinson’s disease
stem cell
