Basal Ganglia Part 1

Question 1

What 6 structures make up the basal ganglia system of gray matter?

Answer 1

caudate, putamen, nucleus acumbens, globus pallidus, subthalamic nucleus, substantia nigra, ventral tegmentum

Question 2

The corpus striatum is made of what?

Answer 2

the caudate and the putamen

Question 3

The globus pallidus is (medial/lateral?) to the putamen?

Answer 3

medial, just underneath it

Question 4

Where is the subthalamus?

Answer 4

at midbrain, just under the globus pallidus, it interconnects the globus pallidus

Question 5

The substantia nigra, Pars compacta and SNpc communicate with the ________with ________neurotransmitter.

Answer 5

communicate with the striatum with DA

Question 6

Starting from the cortex, what is the basal ganglia feedback loop?

Answer 6

cortex–>caudate/putamen–>ex GP/int GP–>thalamus –>cortex
substantia nigra caudate and putamen
subthalamic nucleus int/ext GP

Question 7

What is the direct pathway?

Answer 7

cortex –>+striatum –>inhibits GPi–>less inhibitory signal to thalamus–>greater + from thalamus to cortex–>motor output

Question 8

What is the indirect pathway?

Answer 8

striatum inhibits GPe–> less inhibitory signal to SubTh–>large excit of GPi–>inhibition of thalamus–>less signal to cortex –>decreased motor output

Question 9

How does the striatum inhibit unintended movements?

Answer 9

by increasing GPi activity via the indirect path

Question 10

DA from the SN to the striatum activates the ______ pathway via ____________receptors and inhibits the _______pathway via _________receptors

Answer 10

activates the direct pathway via D1 type DA receptors

inhibits the indirects pathway via D2 type DA receptors

Question 11

What are the four cortico-striate loops?

Answer 11

visual, motivational, executive, motor/premotor (somatosensory)

Question 12

What cortex is involved in the motivational/limbic loop? What part of the basal ganglia does that cortex project to?

Answer 12

the anterior cingulate, OFC project to the nucleus accumbens/ventral striatum

Question 13

What cortex is involved in the executive/cognitive loop?What part of the basal ganglia does that cortex project to?

Answer 13

dlPFC projects to the caudate

Question 14

What cortex is involved in the motor loop? What part of the basal ganglia does that cortex project to?

Answer 14

primary motor, premotor, supplementary motor cortex project to putamen

Question 15

What cortex is involved in the visual loop? What part of the basal ganglia does that cortex project to?

Answer 15

extrastriate cortex (inferotemporal and fusiform gyrus) project to the tail of the caudate

Question 16

Which corticostriate loop projects to the caudate?

Answer 16

the executive/cognitive loop

Question 17

Which corticostriate loop projects to the putamen?

Answer 17

the motor loop

Question 18

Which corticostriate loop projects to the tail of the caudate?

Answer 18

the visual loop

Question 19

Which corticostriate loop projects to the nucleus accumbens?

Answer 19

the motivational loop

Question 20

Where is declarative (episodic/semantic) memory generated?

Answer 20

hippocampus/limbic

Question 21

Where is emotional memory generated?

Answer 21

amygdala (fear conditioning)

Question 22

Where is procedural (non-declarative) memory associated?

Answer 22

cerebellum (motor-skill) and basal ganglia (habit formation)

Question 23

Parallel loops of procedural memory help facilitate what 3 things?

Answer 23

category representation, action selection, insturmental/reward learning

Question 24

Procedural memory is an emergent property of _______

Answer 24

parallel cortico-striate loops

Question 25

Which corticostriate loop is most active in category representation?

Answer 25

the visual loop

Question 26

What structures do declarative visual categories depend on? What kind of memory is this?

Answer 26

depend on hippocampus and prefrontal regions involved in working memory and executive attention (vmPFC, dlPFC). compositional, made of separable elements

Question 27

Describe procedural visual categories

Answer 27

visual cortco-striate loop branches to executive and premotor loops to integrate with executive control. blended, less flexible categories often associated with behavioral responses

Question 28

Describe the mosaic of broken mirrors model of action selection.

Answer 28

overlapping representation of body part with a seen visual object and with an encoded type of movement. utilizes polymodal neurons

Question 29

What is insturmental/procedural learning?

Answer 29

behavioral reinforcement of habit formation. requires extinction of inappropriate learned responses and associated of a stimulus (eg. ball moving towards foot) with a response (eg. kick the ball)

Question 30

What does instrumental and reward learning depend on?

Answer 30

repetitive reinforcement with DA

Question 31

What are the three dopamine pathways from the midbrain to the striatum for reward learning reinforcement?

Answer 31

nigrostriatal: SN to striatum
mesolimbic: ventral tegmentum to nucleus accumbens
mesocortical: ventral tegmentum to PFC

Question 32

Performance of well established behaviors is/is not outcome mediated and is more/less DA dependent.

Answer 32

IS NOT outcome mediated

LESS DA dependent

Question 33

What are the two types of learning?

Answer 33

instrumental (procedural) and reward learning

Question 34

Reward learning is mediated by what loop and what cortical areas?

Answer 34

the motivational loop,

vmPFC, OFC, nucleus accumbens

Question 35

how does DA reinforce reward learning and what DA pathway is involved?

Answer 35

mesolimbic DA innervates the nucleus accumens to strengthen links between behavior and reward

Question 36

Learning occurs in which anatomical direction?

Answer 36

rostral –>caudal

Question 37

What is the sequence of corticostriate loops in reward learning?

Answer 37

motivational loop–>executive loop–>motor loop

Question 38

external triggers activate which loop mainly?

Answer 38

sensorimotor (willfull behavior)

Question 39

internal triggers activate which loops mainly?

Answer 39

motivational and executive