2.29 Basal Ganglia Pathways Flashcards
two basal ganglia pathways
- direct
- indirect
basal ganglia pathways are modulated by this NT
dopamine
How do the direct/indirect pathways work overall?
- antagonistic to one another: both working constantly
- balance help produce smooth movements
What type of NT does the striatum use?
inhibitory NT
Direct pathway allows _______. Indirect pathway _______ to allow for _______ _______.
- movement
- modulates
- smooth movements
outcome of direct pathway activation
activation increases movement
At rest, the direct pathway is ______
inactive
Which two things send GABA-ergic input to the thalamus in the direct pathway (at rest)
- GPi
- SNpr
What does the motor thalamus do normally?
excites motor cortex to initiate movement
What is the result of GABAergic input to thalamus?
- inhibits the thalamus before it can project to the motor cortex
= less movement
direct pathway is _____ at play
active
motor planning region projects to
striatum
striatum projects to
GPi + SNpr » thalamus » motor cortex
Why is the direct pathway active at play?
- cannot inhibit the thalamus
- just because there’s disinhibition, doesn’t go to zero
movement is ______ in the direct pathway at play
increased
disruption of direct pathway leads to ________ (decreased movement)
hypokinesia
indirect pathway outcome
activation decreases movement
indirect pathway at rest: outcome
movement increases
indirect pathway at play: outcome
movement decreases
disruption of indirect pathway leads to __________ (increased movement)
hyperkinesia
Where does dopamine come from (specifically)?
SNpc
What type of neurons does dopamine stimulate?
GABAergic
dopamine signaling favors movement via _______ _______
direct pathway
two types of dopamine receptors
D1 receptor
D2 receptor
D1 receptor
- increases activity of direct pathway
- this is how SNpc has widespread modulation
D2 receptor
decreases activity of indirect pathway
The dopamine pathway ______ movement
increases
Huntington’s
- GABAergic neurons in striatum die: get hyperkinesia
- nothing left to run the indirect pathway
- get major movements all the time
basal ganglia pathways: motor cortex
- lateral corticospinal tract (contralateral)
- rubrospinal tract
lateral corticospinal tract
- distal limb
- fractionate movement
rubrospinal tract
allows for extension of wrist/fingers (UE)
basal ganglia pathways: GPi
- VLPP
- midbrain (reticular formation)
VLPP
ventrolateral pedunculopontine
reticulospinal
- via the VLPP, the reticulospinal tract allows for postural adjustments
- where you get your stepping pattern generators
midbrain (reticular formation)
reticulospinal tract
- stepping pattern generation
