Task 4 Flashcards
(42 cards)
4.1: Which structures are part of the reward system?
fornix, cingulate cortex (CC), parahippocampal gyrus, hippocampus, amygdala, hypothalamus, septal nuclei, mammillary body
4.1: Motivational/Limbic loop in BG –> which structures involved?
ACC, mOFC, ventral striatum, SNr/GPi (limbic territory)
4.1: Mesolimbic dopa pathway
VTA –> nucleus accumbens
4.1: Mesocortical dopa pathway
VTA –> Frontal cortex
4.1: Similarity limbic & motor loop
limbic: stimulus –> outcome
motor: stimulus –> response
- -> both prioritize stimulus with highest outcome & resolve competition between different reward/ motor programs
4.1: Similarity limbic loop & ballot model
both compatible with ballot model; vote for/against stimuli
4.2: What does tonic DOPA mean?
-DOPA neurons are continuously active
4.2: What does phasic DOPA mean?
- DOPA neurons are active in phase ( on – off – on – off - …)
- Phasic activation = burst activity
4.2: Where does DOPA come from?
- Input: from VTA & NA (nucleus accumbens)
- -> From VTA: connected to primary rewards (e.g. food)
- -> From NA: connected to secondary rewards (e.g. money)
4.2: Where does DOPA project to?
DLS (=dorsolateral striatum) & VMS (=ventromedial striatum)
4.2: What does DOPA signify?
-reward neurons –> midbrain DOPA-mediated signals the pure reward of objects
When do midbrain DOPA neurons exhibit phasic activity after?
following primary food & liquid rewards
4.2: When else is DOPA released?
-after prediction error
-show phasic activation following conditioned visual, auditory & somatosensory reward-predicting stimuli
==> signals reward & reward prediction
4.2: How does DOPA respond to a positive reward prediction error (smth unpredicted)?
phasic activation
4.2: How does DOPA respond to a neutral reward prediction error (completely predicted)?
no response of DOPA
4.2: How does DOPA respond to a negative reward prediction error (lower than predicted)?
depression
4.3: How does a conditioned inhibition paradigm work?
test stimulus is presented simultaneously with an established reward-predicting stimulus, but not reward is given afterwards –> test stimulus predicts absence of rewards (conditioned inhibitor)
4.3: Conditioned inhibition paradigm: omission of reward after conditioned inhibitors–> DOPA response?
does NOT lead to a prediction error or response in dopaminergic neurons
4.3: Conditioned inhibition paradigm: occurrence of reward after conditioned inhibitors–> DOPA response?
strong positive prediction error = enhanced activation of dopaminergic neurons
4.3: How does the blocking paradigm work?
stimulus is not learned as a valid reward-predicting, conditioned stimulus if it is paired with an already fully predicted reward
4.3: Blocking paradigm: absence of reward after blocked stimulus–> DOPA response?
NO prediction errror –> NO DOPA response
4.3: Blocking paradigm: reward after blocked stimulus–> DOPA response?
positive-prediction error –> DOPA response
4.3: What does time sensitivity & context dependency of the DOPA signal mean?
- time sensitive: very high –> DOPA neurons are not activated by reward-predicting conditioned stimuli that are predicted by another stimulus with a time course in a range of seconds
- context dependency:
4.3: How do DOPA neurons react to neutral stimuli
combined with rewards?
–> after reward?
–> after cues predicting absence of rewards?
- phasic activation after conditioned reward-predicting stimuli –> response proportional to the subjective value of reward predicted by the stimuli
- depressed activity for cues predicting the absence of rewards
