Motor systems 2- The basal ganglia Flashcards
(13 cards)
1
Q
The Basal Ganglia
A
- integration of sensory and motor input from the cortex
- cortex- BG- cortex loop (via thalamus)
- group of associated subcortical nuclei
- relays back to the cortex via VL thalamus
2
Q
The VL thalamus
A
- motor circuit output to premotor/ SMA cortex
- selection and initiation of V movement
3
Q
The BG at rest (motor loop)
A
- output from BG is inhibiting the thalamus (outflow)
4
Q
during movement (motor loop)
A
- excitatory signal from cortex to BG
- signal switches off BG output
- known as disinhibition (excites BG)
- VLT is disinhibited allowing it to be excited, sends excitatory signal to the SMA
5
Q
within the STR
A
- caudate nucleus
- putamen
- nucleus accumbens
6
Q
within the GP
A
- GPi
- GPe
7
Q
within the SN
A
- SNc (pars recta)
- SNr (reticulata)
8
Q
primary dopaminergic cells are….
A
the pars rectal cells of the SN
- key modulatory role
9
Q
the direct and indirect pathways have…
A
opposing effects on thalamocortical output
10
Q
DA and the direct pathway
A
DA acts on excitatory D1R on striatum- SNr/GPi neuron
- further reduces BG output and facilitates movement via GABA release onto the SNr/GPi
11
Q
DA and the indirect pathway
A
DA acts on D2R (inhibitory) on the striatal- GPe neuron
- reduces activity of the STN and BG output - facilitates movement
12
Q
The direct pathway
A
promotes movement
13
Q
The indirect pathway
A
surpasses movement
