Neurobiology of Decision Making: Phineas Gage and the Somatic Marker Hypothesis

Comprehensive vocabulary flashcards defining key neurobiological concepts, historical case studies, and experimental tasks related to the ventromedial prefrontal cortex and Damasio's somatic marker hypothesis.

Phineas Gage

A 25-year-old railroad construction supervisor who survived an accidental explosion that drove a 13-pound, 3-foot tamping iron through his skull, causing severe damage to his ventromedial prefrontal cortex and dramatically altering his personality.

Tamping Iron

A 13-pound, 3-foot long steel rod used to pack explosive gunpowder into rock holes; in Phineas Gage's accident, it sparked against rock, causing an explosion that propelled the rod through his cheek and skull.

Ventromedial Prefrontal Cortex (vmPFC)

The brain region prominently damaged in Phineas Gage and Patient EVR that connects with the amygdala and hippocampus to regulate emotions, link past choices to emotional consequences, and guide decision-making under uncertainty.

Gage Matrix

A diagnostic dilemma in patients with ventromedial prefrontal cortex damage where standard intellectual abilities and memory remain intact or superior, while real-world decision-making and social behavior become severely impaired.

Antonio Damasio

A neuroscientist who studied patients with prefrontal brain lesions at the University of Iowa and USC, formulating the somatic marker hypothesis to explain the role of bodily emotional feedback in decision-making.

Comptroller

A senior executive position responsible for overseeing all company accounting, financial reports, internal controls, and audits; held by Patient EVR at the exceptionally young age of 32.

Patient EVR (Elliott)

A successful comptroller who underwent surgical resection of a tumor in his ventromedial prefrontal cortex, retaining an IQ in the 99th percentile and intact memory, but losing the ability to learn from mistakes and make advantageous decisions.

Interoception

The ability of the brain, partly mediated by the insular cortex, to perceive, interpret, and understand changes and physiological states occurring within the body.

Somatic Markers

Bodily physiological changes and emotional feelings that mark deliberated scenarios as advantageous or disadvantageous to guide decision-making when outcomes are uncertain.

Somatic Marker Hypothesis

A theory proposed by Antonio Damasio stating that emotional processes and bodily feedback mechanisms guide decision-making, particularly in complex situations where the outcomes of choices are uncertain.

Primary Emotions

Innate or basic learned emotional reactions triggered rapidly by salient features of external stimuli upon brief appraisal of an environmental situation.

Secondary Emotions

Emotional responses acquired by learning the consequences of past events, triggered by thoughts or memories, and stored in the ventromedial prefrontal cortex to guide future actions.

Flat Affect

A state observed in ventromedial prefrontal cortex lesion patients characterized by a lack of emotional reactivity or outward feeling when describing devastating personal failures and traumatic life events.

Iowa Gambling Task (IGT)

A neuropsychological card simulation designed to mimic real-world decision-making under uncertainty, assessing whether individuals learn to avoid high-penalty decks by relying on emotional feedback.

Anticipatory Skin Conductance Response

A measure of autonomic arousal recorded immediately before selecting a card in the Iowa Gambling Task, reflecting the bodily somatic marker generated while deliberating future choices.

Decks A and B (Iowa Gambling Task)

Disadvantageous card decks that offer high immediate monetary rewards of $100$ but impose massive periodic punishments (such as losing $\text{\$}1,250$ on Deck B), leading to a net loss of $-\text{\$}250$ every 10 trials.

Decks C and D (Iowa Gambling Task)

Advantageous card decks that offer lower immediate rewards of $50$ but have much smaller penalties, resulting in a net profit of $+\text{\$}250$ every 10 trials.