Peterson - Basal Nuclei

Question 1

striatum

Answer 1

• caudate nucleus
• nucleus accumbens
• putamen

Question 2

lenticular nucleus

Answer 2

• putamen

- globus pallidus (external and internal segment)

Question 3

substantia nigra (dark segment)

Answer 3

• compact - pigmented nuclei; dopaminergic regulation

- reticular - basal nuclei outputs

Question 4

general inputs and outputs

Answer 4

basal nuclei help control motor functions

• excitatory input to striatum and subthalamic nuclei using glutamate
• inhibitory output by internal globus pallidus and substantial nigra to thalamus using GABA
• excitatory output from thalamus to cerebral cortex using glutamate

Question 5

striatum connections

Answer 5

job is to inhibit globus pallidus and substantia nigra when receiving excitatory inputs from cortex and thalamic nuclei and dopaminergic input from substantial nigra

Question 6

parallel loops

Answer 6

striatum receives different input

• association cortex –> caudate nucleus
• sensorimotor cortex –> putamen
• limbic area –> nucleus accumbens

Question 7

connections to GPe

Answer 7

• excitatory inputs from subthalamic nuclei

- inhibitory outputs to striatum, GPi, SNr, and STN

Question 8

connections to GPi and SNr

Answer 8

• inhibited if receiving inputs from striatum
• excited by STN to go on to inhibit thalamus
• inhibitory effect to thalamus when activated

Question 9

connections to STN

Answer 9

excited by cortex –> excitatory outputs to GP and and SNr

-inhibited by GPe

Question 10

direct pathway

Answer 10

removes inhibition on thalamus

-striatum inhibits GPi –> remove inhibition on thalamus causing it to excite cortex

Question 11

indirect pathway

Answer 11

keep default inhibition on thalamus

-striatum inhibits GPe –> remove inhibition on STN causing excitation of GPi –> inhibit thalamus

Question 12

dopamine effects - indirect vs. direct

Answer 12

• activator in direct path and inhibitor in indirect path
• both paths increase muscle movement
  1. direct
• dopamine binds to D1 activating inhibitory neuron –> inhibit GPi –> less inhibition on thalamus –> excite muscles
  2. indirect
• dopamine binds to D2 inhibiting inhibitory neuron –> less inhibition on GPe –> inhibit STN –> less excitation of GPi –> less inhibition on thalamus –> excite muscle

Question 13

hemiballismus

Answer 13

uncontrolled movement of one arm and leg due to lesion in contralateral sub thalamic nuclei
-damage STN –> do not excite GPi –> more active thalamus

Question 14

Huntington’s

Answer 14

neural degeneration of striatum –> uncontrolled movements (chorea)

Question 15

Parkinson’s disease

Answer 15

reduce pigmentation of substantia nigra compacta –> reduce dopamine –> more inhibition on thalamus –> less muscle movement
-treat with L-dopa or unilateral pallidotomy