19 - Basal Ganglia Flashcards
What are the 5/4 nuclei in the BG?
striatum - putamen, caudate nucleus
globus pallidus GPi GPe
subthalamic nucleus STN
substantia nigra CN
What type of receptor are D1 and D2?
g protein coupled
Does the striatum have D1 or D2 receptor activity?
both!
What type of signal does striatum D1 send to GPi/SN pars reticulata?
What type of signal does striatum D2 send to globus pallidus external?
both inhibitory !!
What external (other than itself) does the BG receive input from?
What sort of of inputs are sent from this structure?
cortex
excitatory
Which nuclei sends excitatory signals within BG?
Which part of BG are these signals sent to?
STN
GPi/SNr and GPe
What are the two pathways in the BG?
go and stop
What structure are in the GO pathway?
cortex -> striatum D1 -> GPi/SNr ->thalamus ->repeats
What structures are in both GO and STOP pathway?
thus what additional are in the STOP?
both: cortex, thalamus, GPi/SNr
STOP+:STN, striatum D2, GPe
DOes the GO pathway include the D2 striatum?
no D1!!
What structures does tonic inhibition happen between?
GPi/SNr -> thalamus
What experimental technique confirmed GO/STOP pathways?
optogenetics
what diseases are associated with BG damage
parkinsons
huntingtons
tourettes
dystonia
WHat is action selection hypothesis?
BG mediates control of action selection
Which is the INPUT nucleus in BG?
Where does this BG structure receive input from?
striatum
all over brain
What are the five bits of evidence for the action selection hypothesis?
1) BG must take input from a wide variety of brain areas
2) there must be some mechanism by which the BG can switch on selected resources
3) there must be evidence of a flow is information between command centres, BG, and associated motor centres.
4) The BG must be able to extract the ‘salience’ or ‘urgency’ of each request
5) There must be evidence of neuronal selection mechanisms in BG
Which are the OUPUT nuclei in BG?
GPi/SNr
If there is low/high exitation input what is output?
opposite
low -> high inhib (tonic inhib)
high -> low inhib
What are the mechanisms for gating motor programs?
tonic inhibition and selective release
