Lecture 27- Emotion II: Reward Flashcards
How does association of fear arise?
-long-term potentiation in the amygdala
What was the rat experiment with self-stimulation?
-certian regions of the brain if stimulated give rise to pleasure -sites in the brain that can directly provide the reward -when pushes the lever then reinforcment -rather push that than anything else -highly motivated behaviour of the brain
What were the sites in the rat brain that were stimulated by the self-stimulation experiment?
-there were many sites but falling along the same bit 1:-most common lateral hypothalamus 2:-basal forebrain=nucleus Accumbens 3:-medial prefrontal cortex, -other regions in the forebrain 4:-then midbrain: (VTA) ventral tegmental area -all along a pathway from the midbrain through the basal forebrain to the prefrontal cortex
What is the pathway of the self-stimulation activation?
-path from ventral medial forebrain to the rostral brainstem, centred around a fibre tract called the median forebrain bundle
What are the fibres running from the VTA to the basal forebrain and medial prefrontal cortex called?
-median forebrain bundle -it is a key structue
What is the median forebrain bundle important for?
-key structure when you want to induce the self stimulation behaviour -it goes from the VTA to nucleus accumbens (part of the basal ganglia) and to prefrontal regions
What is the VTA a source of?-
- the ventral tegmental area is a source (via the median forebrain bundle) of dopamine to prefrontal cortex and associated basal ganglia regions (nucleus accumbens)
What do some hedonic drugs such as opiates facilitate in the VTA?
-release of dopamine by VTA neurons on frontal regions
What do some dopaminergic agonists do?
-e.g. amphetamines -powerful elevators of mood
What are the neurons of the VTA like?
-dopaminergic -VTA is in the midbrain
Where do the VTA neurons project to?
-nucleus acumbens (basal ganglia) -prefrontal regions
What is the pathway involved in addictive behavior in a rat?
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What is the pathway involved in addictive behavior in a human? (the dopamine system)
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What is the VTA like? Size etc.
-relatively small nucleus -large neurons that are fairly scattered in the nuclear region -have projections that are highly divergent -each of the neurons has contact with hundreds and thousands of other neurons in the prefrontal cortex or accumbens -type of synapse is: en passant type, varacose endings -dopamine that is released has modulatory effect, subtly changes their excitability
What is the limbic loop like?
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