Week 11 Flashcards

Question

Decision Making - Value

Answer 1

• Economic models of decision making – first compute value of options and compare • Primary reinforcers – food, water, sex – direct survival benefit – value hardwired but with some flexibility • Secondary reinforcers – money, status – no intrinsic value but association with other forms of reinforcement • Factors in representation of value • Payoff – kind and amount • Probability • Cost (including temporal discounting) • Context – internal or external state, novelty • Preference • Subjective value can be different person to person and hour to hour

Answer 2

Monkeys – electrodes in ACC, lPFC, OFC – reward but manipulate cost, prob, payoff • Choose between 2 pictures – each associated with specific value (juice) • Vary value along one dimension while holding the other 2 fixed • ACC – many cells that responded to all 3 – suggest overall measure of value • If only 1 dimensions – usually payoff or prob • If respond to cost, then usually something else also

Answer 3

• OFC – activation tied to variation in payoff • Striatum – related to effort (cost) • lPFC – probability • mPFC (and lateral parietal) activity correlated with delay b/w action and payoff

Answer 4

• vmPFC (incl OFC) activity correlated with taste preference independent of health • dlPFC associated with degree of control – more activity if preferred but unhealthy item rejected than if same item selected • Hypothesis – vmPFC forecasts short term value, dlPFC evolved later to modulate primary value signals to incorporate longer term considerations • OFC key in value while more lateral modulate control on value representations or actions associated with them

Answer 5

• Subcortical areas represent reward info – dorsal and ventral striatum, HT, amygdala, lat habenula • A lot of work on dopamine – but interplay of many NTs • Dopaminergic cells in midbrain – SN and ventral tegmentum (VTA) • SN project to dorsal striatum (BG and motor circuits) • VTA project 2 pathways • mesolimbic (emotional) – nucleus accumbens (vent striatum), amygdala, hippocampus, ACC • mesocortical – medial FL Dopamine (DA) and reward – Olds and Milner (1954) • Rats with implanted electrodes – can push a lever at will to activate • Some pressed rarely, some constantly • High activity – electrodes activating dopaminergic pathways (recall – PD and l-DOPA and side effects) • More recent – DA activation not related to size of reward but to expectancy of reward – especially active when reward unexpected – role in reinforcement and decision making

Answer 6

``` • Shultz et al. – classical conditioning with monkeys and recording from dopaminergic neurons in VTA • Light (CS) followed by juice (US) • Early training – burst of activity after juice (unexpected reward) • With training – burst after juice decreased and cells started to fire after light (CS) • DA not representing the reward - prediction error • Initially juice not expected so burst when get it • Light not expected but know that it means juice - DA • Learn light/juice relationship – light means juice coming, so getting juice is expected - no DA • Light but no juice – DA after light (light was not predicted) but DA supressed after no juice (negative prediction error) • Repeated withhold juice – response to light decreases and suppression to no juice decreases – extinction ```

Answer 7

• Choosing how to act: integrate incoming info with pre-existing info about goals, values and current social situation • Patient “Elliot” (Damasio 1994) - tumour invading OFC bilaterally • Lack of concern for social rules, decreased social awareness and empathy Anticipation of rewards and punishments (Bechara et al. 1996) • Skin conductance and card selection • Selection followed by reward or punishment • Only controls developed anticipatory SCRs • Patients emotionally insensitive to future outcomes

Answer 8

• Sociopath/psychopath – antisocial personality disorder • Pervasive pattern of disregard for the safety and rights of others - lack of empathy; a tendency to be contemptuous of the rights, interests, or feelings of others; and an excessively high selfappraisal • 3 or more of the following traits: • Regularly breaks or flouts the law • Constantly lies and deceives others • Is impulsive and doesn’t plan ahead • Can be prone to fighting and aggressiveness • Has little regard for the safety of others • Irresponsible, can’t meet financial obligations • Doesn’t feel remorse or guilt

Answer 9

• JS, 56yo male, engineer (Blair and Cipolotti, 2000) • Premorbid: quiet and rather withdrawn, no psychiatric history • Right frontal trauma, incl OFC • High levels of aggression and callous disregard of others • Lack of remorse • Contrast with • CLA: dysexecutive syndrome, no sociopathy • Five prison inmates: developmental psychopathy In contrast to CLA and inmates, JS showed • Poor recognition of visually presented emotions • Reduce autonomic response to visually presented emotions • Poor identification of social behaviour violations: lower skin conductance response and disgust than control Ss • Suggested that impairment is due to a reduced ability to generate expectations of others' negative emotional reactions, in particular anger • In healthy individuals, these representations act to suppress behaviour that is inappropriate in specific social contexts • Propose that the OFC may be implicated specifically either in the generation of these expectations or the use of these expectations to suppress inappropriate behaviour

Answer 10

``` • Long term goals • Short term goals • Hierarchy of goals • Subgoals • Conflicting goals • Habits to supress ```

Answer 11

• Executive function • Use perception, knowledge and goals to bias selection of action and thoughts from many possible • Override automatic thoughts and behaviours • Cognitive flexibility – act and think in novel ways • Cognitive control essential for purposeful goal oriented behaviour • Basic function of the PFC is the representation and execution of organized goal-directed action • Executive functions of the PFC serve that superordinate function in one way or another • Goals of an organism (especially human) vary immensely, so do the timescale and means to achieve them • Also variable are the motives for action and the emotions that accompany it, as well as their influence at any step in the pursuit of a goal • Need plan of action that draws on experience • Tailored to current environment • Flexible and adaptive to deal with unforeseen • Monitor actions and stay on target • Constrain desire and follow rules • Inhibit habits and override urges • Consider 2 PF control systems • Lateral PFC (and FP) • Supports GOB • Works with cortex to form working memory • Planning; simulating consequences; initiating, inhibiting, shifting behaviour • Medial FC • Guiding and monitoring behaviour • Works with lPFC • Monitor ongoing activity to modulate cog control to achieve goals

Answer 12

``` • Input from limbic structures, including amygdala, the thalamus and the striatum, as well as the brainstem • Output to prefrontal cortical areas ```

Answer 13

``` • Was thought to be part of the limbic system (modulation of autonomic responses) • Now shown to have attentional / monitoring functions • Considering and evaluating appropriate goals and subgoals on the basis of affective feedback 1. Dense projections from the ACC to the motor cortex and spinal cord =motor control, esp willed action: overcoming inertia when initiating actions and fighting competing well-established or innate tendencies 2. Reciprocal connections with the lateral prefrontal cortex (PFC) – cognition, esp conflict monitoring (not errors as such, rather the presence of conflict) 3. Extensive afferents from the midline thalamus and the brainstem nuclei point to the importance of arousal/drive state for ACC engagement – increased activation with increased need for arousal ```

Answer 14

• ACC as a way-station / hub / amplifier of emotional signals • Emotional signals can be interoceptive (eg heart rate, breathing) or exteroceptive (meaning in environment eg horrible scenes) • ACC participates in the experiential processing and response to emotion cues – conscious experience of emotion