Flashcards in Principles of Neuroscience Lecture 27 Reward Deck (17)
Describe the divisions in descending control of emotion
Volitional: pyramidal projections
Non volitional, emotional: extra pyramidal
Describe 'Suppression of Behaviour' with reference to a specific example
Humans have the capability to decide when it is appropriate to urinate. We can inhibit the spinal reflex via brain input
What did the Olds-Milner experiment show
There are specific regions associated with pleasure
Rats will press a lever when it causes stimulation of specific areas in the brain
Which regions in the brain are important for reward?
Ventral medial forebrain
Median forebrain bundle
Ventral tegmental area
Describe the limbic loop pathway
1. Cortical input stimulates
2. Striatum, nucleus accumbens, which inhibits
3. Pallidum, which can no longer inhibit
4. Thalamus, which activates
What is the role of dopamine in the limbic loop pathway?
Increases the activity of the loop by further activating the striatum
What is the role of the VTA?
It is the source of dopamine for the basal ganglia
Describe the dopaminergic pathway, and the effects of hedonic drugs on this pathway
Dopamine is released by neurons from the VTA terminating on striatum (nucleus accumbens)
Heroin and nicotine: stimulate the VTA to release more dopamine
Cocaine and amphetamines: stop the reuptake of dopamine by the VTA neurons. Dopamine has longer lasting effects
What happens to the neurons in the brain when the individual is addicted to drugs?
There is a decrease in basal activity
When the olds-Milner experiment was performed on humans, what feeling did the subjects report?
They reported that the effect of dopamine was an anticipation of reward, not reward itself
Describe the difference between wanting and enjoying with reference to a particular experiment
In rats who have depleted striatal dopamine, they will not seek sugar.
However, if they are given sugar, they will still enjoy it.
This shows that there are two different areas for wanting and enjoying
Which region is important for enjoying?
Describe the features of stimulus-reward learning
When we receive a reward, there is increased activity of the VTA
When we are conditioned to that reward, there is no longer an increase in activity when we receive it
If we are conditioned, and we receive the conditioned stimulus but no reward follows, there is extinction of the activity of the neurons in the VTA
Describe how reward undermines motivation with reference to a particular study
In one study there were two groups. One group received a reward when it performed an activity and the other didn't
The second time, neither recieved a reward. The group who initially had had no motivation to perform the activityy
What are modulatory systems of the brain?
What are the general features?
A neuron regulates diverse populations of CNS neurons with various neurotransmitters
1. Diffuse action
2. Nuclei contain relatively few neurons
3. Nuclei in brain stem and basal forebrain
4. Highly divergent
5. En passant connections
What are the four neuromodulatory systems?