Basal Ganglia Flashcards
What are the major part of the Basal ganglia?
1) Striatum
2) Lenticular nucleus
3) Subthalamic nucleus
4) Substantia Nigra
What is the blood supply to the basal ganglia?
Anterior cerebral (penetrating branches:
- anterior part of putamen
- head of caudate
Middle cerebral (lenticulostriate branch)
- body of caudate
- body of putamen
Anterior choroidal artery
- globus pallidus
- tail of caudate
Posterior cerebral artery: thalamus
Parts of the striatum
Caudate nucleus
Nucleus accumbens
Putamen
Parts of the Lenticular nucleus
Putamen
Globus pallidus interna
Globus pallidus externa
Parts of the Substantia migra
Pars compacta
Pars reticulata
What is the venous drainage of the caudate nucleus,
thalamus and internal capsule?
vena terminalis
What is the role of the nucleus accumbens?
- reinforce behaviour by pleasurable effects
- satiety, comfort, sexual satisfaction
- input from limbic system
- output to diencephalon, basal ganglia, frontal lobes
What is the role of the claustrum?
- unknown
- input and out put to all cortex regions
- consciousness of self
What is the role of the stria terminalis?
- input from amygdala
- output to thalamus and septal area
- stress response
- gender identification
List the order of structures in the direct pathway?
Cortex
striatum
GPi + SN
thalamus
List the order of structures in the indirect pathway?
Cortex striatum GPe subthalamic nucleus GPi + SN thalamus
What is the end result of the direct pathway?
more motor activity
What is the end result of the indirect pathway?
less motor activity
What is the role of the caudate nucleus?
- input from cortex
- output to prefrontal areas
- cognitive planning or sequence for conscious goal
- learning and doing new task
What is the role of the putamen?
- input from cortex
- output to motor and premotor areas
- subconscious execution of learned movement
- riding a bike
What is the role of the basal ganglia as a whole?
- indirect influence
- initiate and terminate movements
- suppress unwanted movements
- regulate muscle tone
What is the pathway in lesion in hypokinetic disorders?
direct pathway underactive
What is the pathway in lesion in hyperkinetic disorders?
indirect pathway underactive
List some hyperkinetic disorders
- athetosis (writhing movements)
- chorea (jerky)
- Ballismus (violent large amplitude movements)
- Myoclonus (sudden jerky)
- Huntington disease
What structure is in lesion in Huntington disease?
- basal ganglia and cortex
- striatum first affected
- eventually both pathways affected
How does Huntington disease affect the brain?
- single gene autosomal dominant
* accumulation og huntington protein in nuclei of cells -> trigger apoptosis
What are the symptoms and signs of Huntington disease?
- chorea
- cognitive (short attention, memory, planning)
- apathy, restless, low inhibition, irritable
- death 20yr after onset
What are the symptoms and signs of Parkinson’s disease?
- hyponosmia, fatigue, depression, dementia
- disordered homeostasis : diaphoresis, constipation, hypotension
- difficulty starting movements
How does Parkinson’s disease affect the brain?
- degeneration of SNpc -> deficiency of dopamine sent to striatum
- under activity of DIRECT
- overactivity or INDIRECT
- also affects limbic system, ANS (homeostasis)
What are some underlying causes of Parkinsonism?
- repeated trauma
- toxins
- metabolic disease
- medications
- brain tumour
- Lewy body Dementia
In the direct pathway, what does the cerebral cortex release?
glutamate
In the direct pathway, what does the striatum release?
GABA
In the direct pathway, what do the globes pallidus interna and substantia nigra pars compact release?
GABA
In the direct pathway, what does the thalamus release?
motor output
What does glutamate do? and GABA?
glutamate: excite
GABA: inhibit
In the indirect pathway, what does the GPe release?
GABA
In the indirect pathway, what does the subthalamic nucleus release?
glutamate
