Voluntary Motion Basal Ganglia Karius

Question 1

What do the Basal Ganglia do and how do they do it?

Answer 1

• Control beginning and end of movement
• Basal ganglia work by inhibition and taking the inhibition away to begin movment
• They have an excess of GABA

Question 2

If you don’t have properly working basal ganglia what happens with motion

Answer 2

You cant initiate motion or you get stuck at start of the motion and repeating the stating action

Question 3

What is the direct pathway for basal ganglia motion?

(aka Striatonigal GABAergic pathway)

Answer 3

• Axons from striatum project to the SNPR and GPi
  
  • GPi is internal segment of the globus pallidus
  • SNPR substantia nigra pars compacta
• Presynaptic terminal releases GABA and SNPR and GPi
• Inhgibition of neurons in the SNPR an d GPi

Question 4

Describe the path for direct pathway

Answer 4

• Striatum releases GABA to SNPR/GPi which decreases action potentials to the thalamic nucleus which has less GABA to cortex which releases EAA

Question 5

What is the indirect pathway

Answer 5

1. Axons from the striatum project toe the external segment of the globus pallidus and release GABA. Inhibits GPe
2. AP occurs bc the inhibition has been stopped and Axons from the Globus pallidus travel to the subthalamic nucleus and release GABA
3. Axons from subthalamic nucleus travels to the SNPR and GPi and releases EAA
4. Axons from SNPR and GPi travel to thalamus and rlease GABA so there is a decrease in the EAA release to the cortex

Question 6

What happens in the direct vs indirect path.

Answer 6

• Direct pathway motion occurs by going from striatum releasing gaba in SNPR GPi meaning there is less GABA released in the thalamus so thalamocortical neurons can release EAA in the cortex allowing motion
• Indirect pathway results in no motion occuring. EAA are released from the GPi and SNPR which causes GABA to be released on the thalamic nucleus so it is more inhibited to releasing EAA so motion does not occur

Question 7

What is the source of dopamine in the basal ganglia?

Answer 7

Substantia Nigra Pars compacta

(SNPC)

Question 8

How does dopamine affect direct and indirect pathway

Answer 8

Dopamine increases direct path and decreases indirect path to allow motion to occur