Reward Systems

Question 1

Dopamine role

Answer 1

• mood
• reward
• learning and attention
• movement
• heart rate
• kidney function
• blood vessel function
• sleep
• pain processing
• lactation

Question 2

Dopamine location

Answer 2

• ventral tegmental area (A10)
• substantia nigra pars compacta (A9)
• retrorubral field (A8)

Question 3

Dopamine pathways of the brain

Answer 3

• nigrostriatal (basal ganglia)
• mesolimbic
• mesocorticol
• tuberoinfundibular

Question 4

Mesolimbic pathway

Answer 4

Mediates pleasure and rewarding experiences through the release of dopamine

Question 5

Brain structures involved in mesolimbic pathway

Answer 5

• midbrain
• basal ganglia
• hippocampus
• amygdala
• prefrontal cortex

Question 6

Mesolimbic pathway anatomy

Answer 6

• ventral tegmental area (VTA)
• medial forebrain bundle (MFB)
• nucleus accumbens (NAC)
• limbic system

Question 7

Ventral tegmental area (VTA) role

Answer 7

• reward: motivational salience and associative learning
• orgasm

Question 8

VTA inputs

Answer 8

• nucleus accumbens
• prefrontal cortex
• basolateral amygdala
• brainstem

Question 9

VTA outputs

Answer 9

Reciprocally connected

Question 10

Rostramedial tegmental nucleus (RMTg)

Answer 10

• GABAergic (brake for VTA DA)
• major source of opioid receptors

Question 11

VTA disorders

Answer 11

• schizophrenia
• parkinson’s
• ADHD
• addiction

Question 12

Medial forebrain bundle (MFB)

Answer 12

Neural pathway that connects olfactory, amygdaloid, septal and brainstem regions

Question 13

MFB involvement

Answer 13

• reward
• grief/sadness

Question 14

MFB lesions

Answer 14

Improve L-DOPA induced dyskinesias

Question 15

Nucleus accumbens (NAC) inputs

Answer 15

• VTA DAergic drive on GABAergic MSNs
• prefrontal cortex
• amygdala
• hippocampus
• thalamus

Question 16

NAC outputs

Answer 16

• basal ganglia
• VTA

Question 17

NAC shell

Answer 17

• outer region of the NAC
• part of the extended amygdala
• cognitive processing of reward
• contain D1 and D2 MSNs

Question 18

NAC core

Answer 18

• inner substructure of the NAC
• motor function of reward
• slow wave sleep
• contain D1 and D2 MSNs

Question 19

Limbic system

Answer 19

• motivation
• emotion
• learning
• memory
• connected with NAC

Question 20

Mesocorticol pathway

Answer 20

DAergic pathway that connects VTA to the prefrontal cortex

Question 21

Mesocorticol pathway involvement

Answer 21

• cognition
• working memory
• decision making

Question 22

Mesocorticol pathway schizophrenia involvement

Answer 22

Associated with negative symptoms of schizophrenia such as flat affect

Question 23

Reward prediction error

Answer 23

DA neurons in VTA respond to a presence of a reward

Question 24

Reward prediction error: If a sensory cue predicts reward…

Answer 24

DA neurons fire in response to the cue, not reward

Question 25

Reward prediction error: if reward fails to occur…

Answer 25

DA neurons decrease firing

Question 26

Reward prediction error: unexpected rewards…

Answer 26

Result in higher DA releases and greater learning

Question 27

Incentive salience

Answer 27

- Mesolimbic pathway enhances the motivational properties of cues predictive of rewards - motivational states increase incentive salience of reward and related cues

Question 28

Reward euphoria

Answer 28

- timelocked presence of DA in NAC (voltammetry) - blockade of DA in NAC decreases reinforcing effects in animals

Question 29

Drive of anticipation and cravings

Answer 29

Reciprocal connections from the prefrontal cortex and hippocampus

Question 30

Outputs of VTA DA neurons that fire upon aversive events

Answer 30

- BLA - PFC - NAC