The reward system Flashcards
the reward system
a group of interconnected brain structures involved in motivation, associative learning, and emotions, particularly those associated with pleasure.
systems with a specific function
processing of visual information or generating movement of the fingers
systems with a generic function
systems that process information received from regions performing widely different specific functions to perform a particular behaviorally important operation
what type of system is the reward system
a generic system, because it integrates information from many different areas serving different functions
mesolimbic dopamine circuit
has inputs from the hippocampus to integrate the memory of context, and inputs from the amygdala to integrate the memory of an emotional situation
the nigrostriatal dopamine circuit
reinforces sensory-motor associations, is important in learning new skills and in forming habits
basal ganglia consist of:
- striatum (sensorimotor) and nucleus accumbens (limbic)
- globus pallidus (sensorimotor) and ventral pallidum (libmic)
- substantia nigra (nigrostriatal) and ventral tegmental area (mesolimbic)
- subthalamic nucleus
reinforcement learning
learning the strategy to be taken in a situation that maximises the chance of a successful outcome. reinforcement makes that strategy more likely to be selected in a similar situation in the future.
positive reinforcement releases what neurotransmitter?
dopamine
where is a dopamine signal released?
in the striatum of the basal ganglia
what is the effect of dopamine on the synapse?
increases the strength of synapses, and may lead to LTP
how does information travel in the reward system?
Input is sent from the frontal cortex to the caudate/putamen and from the prefrontal cortex to the NAcc.
Sensorimotor information is sent from the SNc to the caudate/putamen.
Output is sent from the caudate/putamen and from the NAcc to the ventral/globus pallidus, to the thalamus, and to the cortex.
The limbic dopamine pathway sends information from the VTA to the NAcc.
what is the deficit in Parkinson’s disease?
movement execution
what is damaged in Parkinson’s disease?
dopamine transmission in the basal ganglia
dopamine-like drugs
can be used to directly activate receptors for dopamine. these overdrive the reward system, and can reinforce addiction behaviour leading to disordered sensorimotor reinforcement
