Lecture 3 - Pleasure and reward Flashcards Preview

2: Behavioural neurobiology > Lecture 3 - Pleasure and reward > Flashcards

Flashcards in Lecture 3 - Pleasure and reward Deck (16)
Loading flashcards...
1
Q

What are the 3 theoretical components of the brain reward system?

A
  • Learning what is rewarding
  • Motivation (wanting)
  • Pleasure (liking/reward)
2
Q

What neurones produce dopamine, and where do they terminate?

A
  • VTA neurones (ventral tagmental area)

- Terminate in the Nucleus accumbens

3
Q

The midbrain pathways of interest for the dopamine systems originate in A9 neurones – the _______ pathway and
A10 (VTA) ________ and ________ pathways.

A

The midbrain pathways of interest originate in A9 neurones – the nigro-striatal pathway and
A10 (VTA) mesolimbic and mesocortical pathways.

4
Q

The A9 nigro-striatal pathway is involved with _______.
The A10 mesocortical pathway is related to _________.
The _______ path to the nucleus accumbens is the “reward path”.

A

The A9 nigro-striatal pathway is involved with motor control.
The A10 mesocortical pathway is related to perception and motivation.
The VTA path to the nucleus accumbens is the “reward path”.

5
Q

Where are opiates released in response to pleasure or pain?

A
  • Nucleus Accumbens (NAc)
  • Orbito-Frontal Cortex (OFC)
  • Ventral Pallidum (VP)
  • Amygdala
6
Q
  • What is released in the NAc in response to reward wanting?

- What is released in the NAc in response of reward achievement?

A
  • Reward wanting = Dopamine

- Reward achievement = Opioid

7
Q

What is anhedonic state and how does it occur?

A
  • absence of being able to achieve pleasure

- Raised tonic/baseline of dopamine - reduces phasic signal bursts, reducing anticipation of reward.

8
Q

Why may a raised baseline and therefore reduced ability for phasic signal bursts have evolved for survival reasons?

A

It may have evolved to ensure rest and low activity during recovery from injury. (You don’t have to motivation to do stuff therefore you recuperate better)

9
Q

What happens to dopamine neurones:

a) in response to an unexpected reward
b) in response to a predicted reward
c) if a reward was predicted but not recieved

A

a) Increase phasic firing
b) Do not respond
c) Firing is depressed

10
Q

Why (on a dopamine level) do drug addicts need increased doses of the drug in order to be satisfied?

A

Because predictor vs reward is learnt behaviour. If the result is as good as what was predicted, the dopamine reward signal would not fire - so it always needs to be better than predicted.

11
Q

What is the behavioural evidence in the motivation-decision model that indicates that the brans pleasure and pain systems mutually inhibit one another?

A

Pain can be decreased by pleasant experiences such as food, sex, pleasant odours, images and music.
Pleasure (the hedonic experience) is reduced by pain (e.g. appetite reduced by pain).

12
Q
  • Raised tonic/baseline of dopamine - increases/reduces phasic signal bursts, reducing/increasing anticipation of reward.
A
  • Raised tonic/baseline of dopamine - reduces phasic signal bursts, reducing anticipation of reward.
13
Q

Where are opioids released in response to pleasure/pain? (3)

A
Nucleus Accumbens (NAc)
Ventral Pallidum (VP)
Amygdala.
14
Q

What dopamine pathway is associated with schizophrenia?

A

A10 mesocortical pathway

15
Q

What is the action of cocaine at the nucleus accumbens?

A

The opiates bind to opiate receptors that are concentrated in areas within the reward system.
Three neurons participate in opiate action: the dopamine terminal, another terminal containing a different neurotransmitter (probably GABA for those that would like to know), and the post-synaptic cell containing dopamine receptors. Show that opiates bind to opiate receptors on the neighbouring terminal and this sends a signal to the dopamine terminal to release more dopamine. One theory is that opiate receptor activation decreases GABA release, which normally inhibits dopamine release, so dopamine release is increased.

16
Q

What is the dopamine explanation of mania?

A

fMRI studies have shown that manic patients show a reduced dopamine prediction-error signal in the Nucleus Accumbens (compared to normal controls) when an expected reward is not given.
They therefore continue to have optimistic expectations.