dopamine and desire

Question 1

dopamine pathways

Answer 1

• substantia nigra, ventral tegmental area (VTA), amygdala, nucleus accumbens, prefrontal cortex, striatum

Question 2

Parkinson’s overview

Answer 2

• caused by death of dopamine cells in the substantia nigra
• disease initially characterized by motor tremor, later symptom includes cognitive impairments and dementia. symptoms often include reduced executive function
• there is currently no cure for the disease, but some symptoms can be reduced through drugs and deep brain stimulation

Question 3

reward prediction error

Answer 3

• if an unexpected reward occurs, DA neurons become more active and release a burst of DA
• however, if a reward is repedly given after a stimulus (a beep) then the reward will be ‘expected’ and no DA will be released with the reward, but will now be released at the time of the beep
• t/f if a reward is expected and not provided, DA neurons will be suppressed

Question 4

example of money

Answer 4

• recieving money is a positive experience- but it is just paper
• we like money because we learn to associated it with items or activity of value- this reward is symbolic
• real (food and sex)
• virtual- points

Question 5

reward-related cue learning

Answer 5

• ‘symbolic’ value of rewards and its cues can be indexed in behavioral paradigms
• the VMAC was designed to measure propensity to learn reward-related cues even at the expense of adaptive functioning goals

Question 6

cognitive control and reward

Answer 6

• it is currently unclear why attention and cognitive tasks are ‘effortful’ and why task engagement is aversive (our brains are also active when we relax or watch TV
• the feeling of cognitive effort seems particularly linked to working memory and cognitive control
• it is proposed that DA codes both reward and effort costs and that the aversive feeling of cognitive reflects ‘opportunity costs’

Question 7

task persistence- effort and reward

Answer 7

• task persistence is justifiable only while progress outspaces accruing costs.
• cognitive tasks with low success are particularly unpleasant (it feels like a waste of time), and might bias someone towards disengaging and selecting the low cost ‘guess’ option
• poor ability for episodic future thinking is linked with difficulties appreciating and applying knowledge of benefits of delaying gratification
• EGT can be improved through imagery training

Question 8

pokies/gambling

Answer 8

• unpredictability adds a boost to the DA
• if you predictably lost 70% of your money every bet would not be addictive
• if you are unexpected large wins - but still losing 70% of the time- its coded as extremely positive

Question 9

drug addiction

Answer 9

• a chronic relapsing disorder which consists of compulsive pattern of drug seeking and drug taking behavior
• takes place at the expense of other activities
• persists despite adverse consequences

Question 10

cocaine

Answer 10

• coke blocks the reuptake of dopamine in the presynaptic neuron- so increases dopamine because the natural process of upkeeping the amount is lost

Question 11

DA drug- amphetamine

Answer 11

• drugs= ice (most pure) and speed (less pure)
• reverses uptake transporter actively expelling DA and NA out of the neuron which also prevents DA uptake

Question 12

addictive drugs hijack reward response

Answer 12

normal: when reward is expected no additional dopamine is released
addictive drugs: addictive dopamine drugs are ALWAYS coded by the brain as ‘better than expected’

Question 13

animal models of addiction

Answer 13

time out period to prevent overdose. It will continually choose drugs over food until it dies

Question 14

addiction and dopamine

Answer 14

• Addictive drugs produce increased dopamine signaling
  
  • The more DA released the greater the high produced by drugs like coke and ice
    The faster the DA release the more addictive- coupling between the behavior and the high.

Question 15

addiction and free will

Answer 15

• 1sr problem: drugs initiate ‘wanting’ and in addicted people, this leads to drug urges or cravings
• 2nd problem: cognitive control is reduced by impaired function of the prefrontal cortex caused by excessive dopamine
  final result- addictive behavior: failures of top-down control would contribute to loss of control over the urge to take drugs

Question 16

Addiction and dopamine

Answer 16

• not so simple,
• while there is a strong link to Da function and addiction, some drugs do seem to cause addiction with relatively less involvement of DA. possibly depending on the opioid system
• DA system might be more important in the behavior and cognitive control aspects than the pleasant feeling

Question 17

addiction beyond drugs

Answer 17

• cases of addiction exist for most thinkgs which are rewarded
• more individual differences in susceptibility compared to drug addiction