week 11 bio Flashcards
What is association cortex
non-sensory cortex regions across the cortex is a complex distribution and supports our higher cognitive functions
What are the roles of the frontal lobes
primary motor cortex- movement control
premotor areas- planning/guidance of movement
executive control, attention, working memory and top down control
The frontal lobes
about 1/3 of the cerebral cortex in all mammalian species has tremendous evolution expansion and is the seat of intelligence and abstract thinking
Prefrontal cortex
most anterior portion of the frontal lobe, highly interconnected with rest of brain, Once thought to be functionally insignificant
Who was Phineas Gage
Famous neurological patient: dramatic prefrontal damage, source of early insight into how brain controls behaviour
What is the case of Phineas Gage
Before- average intelligence, very industrious and dependable, energetic and persistent in executing all of his plans of operation
After: Gage was no longer Gage, No obvious motor or memory impairments, Mainly affected personality, impaired concentration rude and aimless
What are Lobotomy patients
Surgical separation of portion of frontal lobes form rest of brain, treatment for mental disorders, early report miraculous recoveries but- severe negation effects on a patient’s personality and ability to function independently
Modern evidence
Prefrontal lesions- various unusual emotional, motor and cognitive changes
What is lateral surface
closet to the skull anterior to the premotor areas and the frontal eye fields
What is medial surface
lies between the two hemispheres and to the front of the corpus callosum and anterior cingulate cortex
What is the orbital surface
Above the orbits of the eyes and the nasal cavity. the orbitofrontal cortex is closely related to the ventral medial surface
What is executive functions
aka executive control or cognitive control
What are the 3 main cognitive capacities
Inhibition- overcoming a prepotent response
Updating/WM- maintenance, monitoring updating, manipulation of the STM contents
Shifting/ cognitive flexibility- flexibly switching between tasks and behaviours
peripheral frontal cortex
larger PFC volume and greater PFC thickness associated with better executive task performance
What is PFC and top-down control
top down control when goals or plans are involved in actions
PFC- as gating filtering biasing mechanism of neural activity
What is Stroop task
Measures ability to inhibit a prepotent response name of a colour and colour of font and incongruent colour where name of the colour and colour of font has different colour
What is testing response inhibition
Go/No-Go task- respond to go trials presented majority of time
Stop-Signal reaction time- stop signal present after go:
measure stop action delay
Lateral PFC implicated, particularly inferior frontal region
What is planning and problem-solving
Patients with lateral PFC damage: slower+ more moves to solve
fMRI: ToL activates right DLPFC
What is Wisconsin Card Sorting Test
Measures how well people adopt to the changing rules, 3 different ways to classify each card: colour, shape, Number rules change
Patients with frontal lobe damage: make more errors, can’t keep track of the rule change, longer reaction times
What is the issue with assessment of frontal lobes
Most complex aspect of neuropsychological assessment, Few sensitive test available, Isolated cognitive function may be unimpaired, ecological validity, lack of insight
detecting executive function impairments
The frontal lobe paradox, people with impaired PFC function can be unaware of problems and deny they need help/support knowing-doing disassociation. Not knowingly denying truth: reflects the fact that the areas of the frontal lobes that are responsible for self-monitoring and developing insight have been affected by their brain damage
Effect of multi tasking
patients with PFC lesions may be particularly impaired at multi-tasking hold goals in mind while performing or processing secondary subgoals
Hot versus cold control processes
distinction between the control of affective or reward-related stimuli (hot) versus purely cognitive (cold) stimuli
Hot cognitive control involves primarily the orbitofrontal cortex whereas cold cognitive control involves primarily the lateral PFC
What is Iowa gambling task
aim is to win as much money as possible
patients with orbitofrontal cortex dysfunction continue to persevere with the bad decks, sometimes even though they know that they are losing money overall
What is LPFC vs OFC delay discounting
delay discounting also point to a difference between the lateral and orbital PFC
Delay discounting preference for smaller immediate rewards over larger delayed rewards
Patients with OFC/VM lesions fail to plan ahead and exhibit impulsive behaviour by opting for immediate rewards
PFC is crucial for using information to guide behaviour
working memory- active maintenance of goal-related information in the face of distractors/interference; task-dependent
Delayed response task: requires response to stimuli that saw/heard a short while earlier DLPFC shows increased activity during delay period: stronger activation; better memory performance
What is insight into WM from neuroimaging
Neuroimaging studies show that working memory is mediated by frontal cortex and several posterior cortical regions, posterior cortical regions seems to specialise in the type of information held in working memory, Frontal area may have a special role in integrating information
