Self control and reward-seeking behaviour

Question 1

Defining self-control

Answer 1

The ability to resist temptation and override impulsive responses in order to behave consistenly with out long term goals - (Hassin et al., 2010)

Question 2

Top down processing

Answer 2

overriding urges - rational and thoughtful goal directed behaviour - cerbral cortex and PFC (especially lateral PFC) involved in this

Question 3

Bottom-up proccessing

Answer 3

letting desires in the moment direct behaviours, reflexive, environmentally triggered, urges and desires in the moment - more primitive structures invoved (brain stem, limbic system (amygdala, hypothalamus)

Question 4

Top-down vs Bottom-up

Answer 4

tension between brain functioning, top-down PFC is in control being very thoughtful but can conflict with bottom-up processing where envrionment triggers urges coming from amygdala and ventral striatum that are really sensitive to potential rewards

Question 5

Successful self-regulation

Answer 5

top-down control from PFC over subcortical regions involved in reward and threat processing

Question 6

Failed self-regulation

Answer 6

top-down control is diminished from PFC or when the balance in activity favours threat and reward system, less activity in PFC, so less likely to control ourselves.

Question 7

Brain structure and self-control (in terms of PFC and amygdala - volume and thickness)

Answer 7

Structural MRI scans of cortical thickness and volume - THINNER cortical thickness of PFC predicted lower dietary self control and HIGHER volume of amydgala predicted lower dietary self-control (giving into urges and impulses)

Question 8

Balance model of self control - Lopez et al (2017)

Answer 8

Interest in dietary control - hypothesis that self control failures result from an IMBALANCE in reward and executive control mechanisms (balance between PFC and amygdala explaing whether our self control suceeds or fails)

Question 9

Balance model of self control - research / fMRI results (Lopez et al., 2017)

Answer 9

fMRI looked at chronic dieters when giving into food desires (failures in self-control) - suggetsed behaviours predicted by the BALANCE of activity, not just activity in one system alone

Question 10

Cognitive control over temptation - (Kober et al., 2010)

Answer 10

fMRI using cognitive strategies to regulate cravings for cigarettes and food images.
* Cognitive strategy: think about the long-term consequences of repeatedly consuming the item (items such as cigarettes or unhealthy food)
* Significantly reduced cravings for individuals in the long term category
* Down-regulation of craving was associated with
* Increased activity in the prefrontal cortex
* Decreased activity in the ventral striatum (really important for rewrads), amygdala and ventral tegmental area

Question 11

Nucleus accumbent - located in the ventral striatum - Lopez et al. (2014)

Answer 11

fMRI presnted with food images - 1 week self report of desires - HIGHER nucleus accumbens activation to food cues predicted - stronger food desires/ higher amount eaten - this is due to being associated with reward

Question 12

Smaller sooner vs larger later research - Anandakumar et al. (2018)

Answer 12

Would you prefer £7 now or £10 in a month?”
* Stronger preference for smaller-sooner rewards = higher impulsivity, impatience, poorer school performance, increased substance abuse…

Question 13

Modifying brain activity in self-control

Answer 13

Lesions, rTMS, tDCS, mindfulness

Question 14

Lesions and impulsivity

Answer 14

131 combat veterans with traumatic brain injury
* Damage to prefrontal cortex associated with INCREASED impulsivity

Question 15

Limitations of lesion studies

Answer 15

different areas of brain affected in different indiviudlas AND possibility of functional re-organisation following injury

Question 16

How to get around limitations of legions?

Answer 16

Experimentally creating transient “lesions”
* rTMS: repetitive transcranial magnetic stimulation
* Low frequency rTMS: decreases excitability, i.e. reduces likelihood of neurons firing
* Creates a temporary “lesion” effect

Question 17

rTMS and patience for rewards (smaller now or larger later) - Figner et al.(2010)

Answer 17

• Applied low-frequency rTMS to inhibit left lateral PFC
• Offered smaller rewards now or larger rewards later
• Found tempory lesion - did not alter how attractive participants rated the rewards as however…
• Participants were less patient (less likely to wait for a larger reward) would go for the immediate reward
  Adds to evidence PFC is CRUCIAL in top down more patient, goal directed behaviours.

Question 18

tDCS and risk taking - Gilmore et al.(2017)

Answer 18

participants choose whether a token is hidden in a red or blue box - less likely option(risky) has a higher reward - TDC activate right dlPFC - compared to placebo this activation caused LESS risk taking

Question 19

Mediation and self control brain circuits

Answer 19

smokers vs non-smokers -