basal ganglia

Question 1

what are the contents of the basal ganglia ?

Answer 1

substantia nigra
subthalamic nucleus
putamen
caudate nucleus
globus pallidus

Question 2

what is the striatum ?

Answer 2

both the putamen and the caudate , divided by the internal capsule

Question 3

what is the lentiform nucleus ?

Answer 3

the putamen and the globus pallidus

Question 4

what does the direct vs the indirect pathway do ?

Answer 4

the direct pathway initiates movement
indirect pathway stops movement

Question 5

how does the direct pathway start ?

Answer 5

1- the cortex stimulates the striatum through glutamate
2- the striatum sends GABA to thr GPi to inhibit it , GPi is normally inhibitory anyway - so we inhibit the inhibition
3- this activates the thalamus and sends signals to the cortex to allow for movement

Question 6

how does the indirect pathway start ?

Answer 6

1- the cortex stimulates the striatum through glutamate
2- the striatum sends GABA to the GP externa which inhibits the inhibitory effect on the subthalamic nuclei
3- the STN activates the GPi , which inhibits the thalamus , this suppresses the movement

Question 7

what are the modifiers associated with each pathway ?

Answer 7

direct pathway modifier : the striatum gets dopamine from the substantia nigra , D1 receptor respond to this dopamine and allow for movement to happen
indirect pathway modifier: same thing but bind to D2 which slows down movement

Question 8

what are the diseases associated with this pathway ?

Answer 8

parkinsons - associated with destruction of the substantia nigra - meaning there is less dopamine , less direct more indirect

Huntington - striatum affection no indirect pathway which means there is too much movement - chorea

hemiballismus - STN affection meaning there is less indirect , wild flinging movement

wilsons affects the GP internus

Question 9

what is Sydenham chorea ?

Answer 9

chorea associated with autoimmune destruction of the basal ganglia
associated in children who have rheumatic fever