Wk3 - Positive Affect Flashcards
Why is positive affect studied less than negative affect?
Negative affect is seen as being more important to study because it gives us information about pathological conditions
More likely to get funding for anything that could help find a cure for a psychological illness
Less likely to get funding to study happiness/positive affect
Positive affect is more difficult to measure than negative affect
Is positive affect dependent on cortical or sub-cortical structures?
Sub-cortical structures
Which 3 sub-cortical structures is positive affect dependent on?
Ventral striatum
Ventral tegmental area (VTA)
Nucleus accumbens (NAcc)
Which 3 sub-cortical areas make up the reward network?
Ventral striatum
Ventral tegmental area (VTA)
Nucleus accumbens (NAcc)
Is the amygdala associated with positive or negative affect?
Both
Are there any anatomical differences in terms of the amygdala and positive and negative affect?
No. Studies of emotion have found the peak coordinates of emotional amygdala activation to be the same for positive and negative effect.
Who discovered the role of the nucleus accumbens?
Robert Heath
What is the role of the nucleus accumbens?
To produce very positive feelings
Produces euphoria
Can produce hedonic laughter in Parkinson’s Disease patients
What contradictory study was conducted to investigate the role of the nucleus accumbens in positive affect?
Robert Heath implanted electrodes into the subcortical regions invovled in the reward system and attached them to a button.
Chronically depressed patients would self-administer electrical stimulation by pressing a button
What did this contradictory study of the NAcc find?
When depressed patients electrically stimulated regions including the NAcc, they would induce pleasure / pleasant sensations / positive feelings
What structure in the reward system is active during male orgasms?
Increase of activity in the ventral tegmental area (VTA)
What structure in the reward system is active during a heroin high?
Ventral tegmental area (VTA)
What can VTA findings suggest about the relationship between heroin addicts and sex drive?
Heroin addicts have decreased sex-drive
Possibly this is because they are accustomed to their VTA being activated in response to drugs (VTA has learned to react to the artificial reward of the drugs)
Their VTA is activated less during orgasms, thus decreasing their sex-drive
How can drugs affect people’s reward system?
Drug addicts tend to not have a normal reaction in their reward system to natural rewards
Their reward system learns to become artificially activated in response to drugs and becomes less responsive to natural rewards (e.g., orgasms)
What type of study looked at male orgasms and VTA activity?
PET study
What areas of the brain were found to be active during female orgasm?
Ventral midbrain
Caudate nucleus (basal ganglia)
What region of the brain decreased during female orgasm?
Orbitofrontal metabolism decreased
What is the left orbitofrontal region associated with?
Behavioural control
How does less activation in the left orbitofrontal region link with pleasure?
There is decreased behavioural control.
Release from inhibition goes along with increased pleasure.
How do drugs such as cocaine and amphetamines increased dopamine available in the synapse?
They bind with DA transporters and block them.
The blockade of DA transporters enhances DA’s efficacy.
What type of drug is cocaine?
Mono-amine uptake blocker
How do opiates work?
Disinhibit the VTA
Direct effects on dopamine terminals
Cause a release of dopamine in the striatum
Increase the amount of dopamine available in the synapse
How can we stop self-administration of heroin?
Block the opioid receptors in the VTA or the nucleus accumbens
These areas don’t receive the dopamine that they normally would during heroin administration
Rewarding feeling is no longer there
People stop self-administering heroin
What effect do psychostimulants have on dopamine levels?
Psychostimulants induce positive affect by increasing dopamine levels in the ventral striatum
This gives evidence for dopamine in these reward-related structures being related to positive affect
What is a complication of research focusing on reward the reward system in terms of wanting vs liking something?
The study of brain activity during drug-taking/drug-seeking has suggested that parts of the reward system may be more strongly involved in WANTING a substance, rather than actually liking or enjoying a substance
What did an fMRI study of cocaine self-administration find about brain activity correlations with the ‘high’?
The ‘high’ NEGATIVELY correlated with nucleus accumbens activity
Positively correlated with the substantia nigra
What did an fMRI study of cocaine self-administration find about brain activity correlations with the ‘craving’?
Craving POSITIVELY correlated with the nucleus accumbens BOLD signal
Describe the fMRI study of cocaine self-administration
People would self-administer cocaine
Self-reported their amount of high they felt and the amount of craving they felt at different points during the self-administration
What is the nucleus accumbens related to?
The craving/wanting of pleasure
What non-chemical experience shows increases in reward-related areas?
Listening to music
What are some benefits of listening to music?
Induces feelings of pleasure
Induces physical responses such as thrills, chills, shivers, or change in heart rate
Outline a study that was conducted using pieces of music and pieces of scrambled music
Participants placed in fMRI scanner
Participants rated music pieces and scrambled music pieces for pleasantness and unpleasantness
What type of analysis was used to assess music-related brain activity?
Functional connectivity analysis
What was the purpose of the scrambled-music condition, since this was not predicted to induce pleasure?
Acted as a baseline condition for a contrast
What did the researchers aim to look at in the music study?
The researchers wanted to see which parts of the brain were more/less active and which parts of the brain were active together/synchronously and correlating
What did the music study find regarding areas of the brain that were active in response to the normal music pieces?
Increased brain activity in the nucleus accumbens, VTA, hypothalamus, and insula
Which brain area responses were correlated in the music study? What does this suggest?
VTA and NAcc
Suggests as association between dopamine release from the VTA and NAcc response to music
Where was there a strong functional connectivity in the music study?
There was a strong functional connectivity between the nucleus accumbens and the VTA
What is the VTA the site of?
The VTA is the site of mesolimbic dopamine neuron cell bodies that project to the NAcc
What is dopamine release by the VTA crucial for?
Reward processing
