Brain Substrates Flashcards
what is the role of the dorsal striatum?
links the stimulus with the response (S-R part)
*linking discriminative sitmuli to behavioral contingencies
what is the dorsal striatum comprised of?
caudate and putamen
describe the relationship between the dorsal striatum and the motor cortex
dorsal striatum receives highly processed sensory information and projects to motor cortex which produces response
what happens if you make a lesion to the dorsal striatum?
*problems of operant conditioning
1. simple S-R relationships are learned correctly (e.g., press lever, get food)
2. no learning with discriminative stimuli (if light is on, then lever press yields food)
what role does the orbitofrontal coretx play?
linking responses with outcomes (R-O part)
*learning to predict outcomes of behavior
*receives input from sensory modalities and visceral sensations
what does the OPFC control?
social and emotional responses, utilization (goal directed) behavior, evaluates potential consequences
what happens in the OPFC during operant conditioning?
- neurons selectively respond to rewarding or punishing consequences
- OPFC sends feedback down to DORSAL STRIATUM to help initiate motor response
- OPFC evaluates potential consequences
- OPFC helps to choose between actions (based on potential consequences)
define hedonistic value
things we like
define motivation value
things we will work for
what is the VTA (ventral tegmental area)
- found in the brainstem
- one of the wanting pleasure centers
- contains dopamine-producing neurons which project to the frontal cortex
when will a reinforcer strengthen the S-R association?
Only when “wanting” and “liking” signals are both present will the arrival of the reinforcer evoke responding and strengthen the S-R association.
what is the SNc (substantia nigra pars compacts)?
- one of the pleasure centers
- part of the basal ganglia that contains dopamine-producing neurons that project to the striatum
what effect do primary and secondary reinforcers have on dopamine outputs?
increase dopamine output from both VTA and pars compacts
what happens if you decrease dopamine output in both VTA and pars compacta?
can still judge how much you like something as well as someone who isn’t impaired, but won’t be motivated to work for it
define the incentive salience hypothesis
The hypothesis that dopamine helps provide organisms with the motivation to work for reinforcement.
- increase in DA = increase in wanting or craving
-no DA, no motivation
describe the rat experiment for incentive salience hypothesis
*control rats and rats given dopamine antagonist
*both prefer sugar pellets
*control rats willing to work and press lever to get sugar pellets
*IV rats would just eat rat chow to avoid working for food
describe Sheffield’s consummatory response theory
it’s the behavior itself that is rewarding, not the food
how is liking in the brain registered?
through the opioid system. primary reinforcers increase release of opioids - may be related to satiety as well as please.
*some secondary reinforces and behaviors increase opioid release as well
what is the insular cortex (insula)?
- determines IF something is punishing
- important for conscious awareness of our bodies and emotional states
- encodes intensity of pain and negative emotions - hunger, anger, disgust, social rejection
describes what occurs when the insula is damaged
damage to insula, can not learn to avoid punishment. However, can still learn reinforcement
what is the relation between insulate activity and punishment?
insulate activity is proportionate to punishment. the greater something is perceived as punishing, the greater the insula activity
what is the dACC (dorsal anterior cingulate cortex)?
- involved in the motivational value of pain (punishment). how much you learn from it
- it detects unexpected events and suggests an appropriate response
