PSYC 3380_Chapter14.pdf

PSYC 3380 – Cognitive Neuroscience Executive Functions Lecturer: Ezgi Palaz, MSc Executive Functions The complex processes by which an individual optimizes their performance in a situation that requires the operation of several cognitive processes Executive functions are not tied...

PSYC 3380 – Cognitive Neuroscience Executive Functions Lecturer: Ezgi Palaz, MSc Executive Functions The complex processes by which an individual optimizes their performance in a situation that requires the operation of several cognitive processes Executive functions are not tied to one particular domain (memory, language, perception, etc.) but take on a role that is meta-cognitive, supervisory, or controlling Related to prefrontal cortex Prefrontal Cortex (PFC) Prefrontal Cortex (PFC) Problem-Solving Problem-solving is often tested by giving an end point (a goal) and, optionally, a starting point (a set of objects) and participants must generate a solution of their own Tower of London, FAS test, Cognitive Estimates Test Prefrontal cortex lesions often lead to poor problem solving. https://www.youtube.com/watch?v=IiBJ94HRpeM Overcoming Habitual Responses Inhibition: reducing the likelihood of a particular thought/action. Related to medial PFC, specifically anterior cingulate cortex & pre- SMA ◦ Stroop: name the color of the ink and ignore reading the color name (overcome habitual response) Overcoming Potent Responses Inhibition: reducing the likelihood of a particular thought/action. Related to medial PFC, specifically anterior cingulate cortex & pre- SMA ◦ Go/No-Go: respond to a frequent stimulus (go trials) but withhold a response to another stimulus (no-go trials) (overcome potent response) Task Switching Discarding a previous schema and establishing a new one requires PFC activation. PFC damage leads to perseveration (failure to shift) In the Wisconsin Card Sorting Test, patients are given a card that can be sorted by a number of rules (matching shape, number, or color). Sometimes the rule unexpectedly changes, and the patients must adjust their responses to the new rule. Task Switching Switch cost: A slowing of response time due to discarding a previous schema and setting up a new one. Related to inhibiting old task, therefore it is more costly to switch from harder to easier. Task switching is also related to ACC/pre-SMA Multi-Tasking Carrying out several tasks in succession; requires both task switching and maintaining future goals while current goals are being dealt with Patients with lesions to the anterior prefrontal cortex may be particularly impaired at multi-tasking, even though each task in isolation may be successfully performed and even though they perform normally on other tests of executive function Six Element Test: Patients with prefrontal lesions would often fail to switch tasks, spend too long planning (e.g. taking notes) but never execute the plans, and so on. The patients could easily perform the isolated tasks, but their difficulties were only apparent when they had to coordinate between them Decision Making Decisions do not solely rely on rationality, even without brain damage. Framing or social justice perception (i.e., ultimatum game) can affect decisions. ACC, OFC Somatic Marker Hypothesis Hot stimuli vs. cold stimuli SMH states that somatic markers form the link between previous situations stored in the cortex and the “feeling” of those situations stored in regions of the brain dedicated to emotion (e.g., the amygdala) and the representation of the body states (e.g., the insula) Somatic markers are stored in the vmPFC and have a direct role in controlling ongoing behavior, notably in those situations in which feelings are critical (e.g., when taking risk, or interacting socially) Iowa Gambling Test Delay Discounting Current reward vs future reward Whether to go on holiday this year or invest the money for a better holiday in the future? OFC lesions lead to planning failure and impulsive behavior Different rewards at two future points in time → lateral PFC Multiple Demand Network Subdivisions of lateral PFC? No, it is one network Lateral PFC, ACC, intraparietal sulcus are claimed to be involved in cognitive control Fluid vs crystallized intelligence Posterior- Anterior Organization Hemispheric Differences Not found in other primates – humans are more lateralized. Left lateral PFC is considered to be specialized in problem solving while right is for task monitoring (process of relating information currently held in mind back to the task requirements → involves keeping “on task” and maintaining the currently relevant rules) Alternative views Anterior Cingulate Cortex (ACC) Considered part of limbic system Recently been described in functionally two different regions: dorsal ACC: Strong connections with the dlPFC, cognitive division Rostral ACC: limbic connections, affective division Anterior Cingulate Cortex (ACC) Involved in error detection. In human reaction time experiments, the trial immediately after an error (error + 1) tends to be slower and more accurate than after a correct trial (correct + 1) ◦ A cognitive mechanism that monitors for errors and recalibrates task performance accordingly (e.g., slowing down to ensure greater accuracy). ◦ Event-related fMRI shows anterior cingulate activity on the error trial, with greater activity on the error + 1 trial in the lateral prefrontal cortex associated with behavioral adjustment