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Basal Ganglia
Neuroscience
31
Medical
Professional
04/27/2011

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Term
Where is basal ganglia partially derived from?
Definition
telencephalon
Term
What makes up the striatum
Definition
caudate nucleus and putamen
Term
How are the caudate nucleus and putamen separated
Definition
anterior limb of the internal capsule
Term
What is the lentiform?
Definition
putamen, internal and external segments of globus pallidus
Term
What are the three major inputs to the striatum?
Definition
Corticostriatal fibers
centre Median
Substantia Nigra
Term
Corticostriatal fibers
Definition
area 4 and 6- densest projection
frontal area project to head of caudate
everything else- body and tail
Uses GLUTAMIC ACID
Term
Centre Median
Definition
nucleus of thalamus sending projections
Term
Substantia Nigra
Definition
high concentration of Dopamine
Term
where is acetylcholine located?
Definition
striatal interneurons
Term
where is GABA located?
Definition
present in interneurons and bulk of striatal outputs
Term
Where does serotonin come from
Definition
raphe nuclei
Term
Explain the outputs of the striatum
Definition
substantia nigra and globus pallidus
both project to subthalmic nucleus
subthalmic projects to SUBSTANTIA NIGRA and INTERNAL GLOBUS PALLIDUS
Term
where does the subthalmic nucleus receive input from
Definition
also from the cortex
Term
Where do the main outputs of the basal ganglia arise?
Definition
internal pallidum and substantia nigra
they both project to thalamus (VA and L) and midbrain tegmentum.
Term
what are the major outputs of the basal ganglia? inhibitory or excitatory?
Definition
inhibitory GABA
Term
What happens at the level of the thalamus with the basal ganglia?
Definition
basal ganglia inputs indirectly work with cerebellum-->thalamus-->project to areas 4 and 6 in cortex
Term
What happens at the midbrain tegmentum with the basal ganglia
Definition
descending BG interacts with RAS and mesencephalic locomotor region
Term
what is the origin of the readiness potential?
Definition
cortical and subcortical
600-800 msec
Term
when do neurons in area 4 begin firing?
Definition
250 msec before movement
Term
these are one second in duration preceding a voluntary movement
Definition
VL of thal, medial globus pallidus, and area 6
Term
This nucleus is responsible for complex tasks ONLY
Definition
caudate nucleus
just sequencing and order of learned movements
Term
What is Parkonsonism characterized by?
Definition
akinesia (cant initiate)
rigidity
tremor at rest
Term
What causes Parkison's?
Definition
marked decrease in Dopamine from substantia nigra
Term
What are some treatment options for Parkinsons
Definition
L-Dopa therapy
Thalotomy
bilateral pallidotomy-lesion the internal pallidum--> known to restore gait and function.
Term
what is hemi-ballismus
Definition
damage to subthalmic nucleus (dampens BG outputs)
Leads to irregular swinging of arms
Term
athetosis?
Definition
slow distal movements and chorea.
Term
a lesion of the nigra results in
Definition
akinesia
Term
a leasion of the caudate leads to
Definition
chorea
Term
a lesion of the subthalamus leads to
Definition
hemiballisumus
Term
a lesion of the putamen leads to bradykinesia
Definition
Term
Disinhibition of the nigra leads to
Definition
ballismus
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