2.29 Basal Ganglia Pathways

Question 1

two basal ganglia pathways

Answer 1

• direct

- indirect

Question 2

basal ganglia pathways are modulated by this NT

Answer 2

dopamine

Question 3

How do the direct/indirect pathways work overall?

Answer 3

• antagonistic to one another: both working constantly

- balance help produce smooth movements

Question 4

What type of NT does the striatum use?

Answer 4

inhibitory NT

Question 5

Direct pathway allows _______. Indirect pathway _______ to allow for _______ _______.

Answer 5

• movement
• modulates
• smooth movements

Question 6

outcome of direct pathway activation

Answer 6

activation increases movement

Question 7

At rest, the direct pathway is ______

Answer 7

inactive

Question 8

Which two things send GABA-ergic input to the thalamus in the direct pathway (at rest)

Answer 8

• GPi

- SNpr

Question 9

What does the motor thalamus do normally?

Answer 9

excites motor cortex to initiate movement

Question 10

What is the result of GABAergic input to thalamus?

Answer 10

• inhibits the thalamus before it can project to the motor cortex

= less movement

Question 11

direct pathway is _____ at play

Answer 11

active

Question 12

motor planning region projects to

Answer 12

striatum

Question 13

striatum projects to

Answer 13

GPi + SNpr » thalamus » motor cortex

Question 14

Why is the direct pathway active at play?

Answer 14

• cannot inhibit the thalamus

- just because there’s disinhibition, doesn’t go to zero

Question 15

movement is ______ in the direct pathway at play

Answer 15

increased

Question 16

disruption of direct pathway leads to ________ (decreased movement)

Answer 16

hypokinesia

Question 17

indirect pathway outcome

Answer 17

activation decreases movement

Question 18

indirect pathway at rest: outcome

Answer 18

movement increases

Question 19

indirect pathway at play: outcome

Answer 19

movement decreases

Question 20

disruption of indirect pathway leads to __________ (increased movement)

Answer 20

hyperkinesia

Question 21

Where does dopamine come from (specifically)?

Answer 21

SNpc

Question 22

What type of neurons does dopamine stimulate?

Answer 22

GABAergic

Question 23

dopamine signaling favors movement via _______ _______

Answer 23

direct pathway

Question 24

two types of dopamine receptors

Answer 24

D1 receptor

D2 receptor

Question 25

D1 receptor

Answer 25

• increases activity of direct pathway

- this is how SNpc has widespread modulation

Question 26

D2 receptor

Answer 26

decreases activity of indirect pathway

Question 27

The dopamine pathway ______ movement

Answer 27

increases

Question 28

Huntington’s

Answer 28

• GABAergic neurons in striatum die: get hyperkinesia
• nothing left to run the indirect pathway
• get major movements all the time

Question 29

basal ganglia pathways: motor cortex

Answer 29

• lateral corticospinal tract (contralateral)

- rubrospinal tract

Question 30

lateral corticospinal tract

Answer 30

• distal limb

- fractionate movement

Question 31

rubrospinal tract

Answer 31

allows for extension of wrist/fingers (UE)

Question 32

basal ganglia pathways: GPi

Answer 32

• VLPP

- midbrain (reticular formation)

Question 33

VLPP

Answer 33

ventrolateral pedunculopontine

Question 34

reticulospinal

Answer 34

• via the VLPP, the reticulospinal tract allows for postural adjustments
• where you get your stepping pattern generators

Question 35

midbrain (reticular formation)

Answer 35

reticulospinal tract

- stepping pattern generation