Lecture 10&11 - Executive Functions Flashcards
- remember! different brain cuts (views on the brain)
- axial = from abive
- sagittal = from left/right
- coronal = from front/back
- self-reflection brain mode?
the default mode
- superior temporal sulcus (STS) active when …
body actions are meaningful and goal directed (expectancy violations)
executive functions - their role (basics)
- supervisory role; directing cognitive functions (goal directed), in prefrontal cortex
- modulate activity of other cognitive functions; modifying/adapting rules, adapt to environment, within working memory (maintaining rules)
brain regions for executive functions
- > frontal lobe (higher cognitive functions)
- bilateral prefrontal cortex (learning)
- lateral prefrontal cortex
- medial prefrontal cortex
- basal ganglia
- > connections to other regions
establishing and modifying rules (executive functions)
- initiating new rules, inhibiting inappropriate rules (-> actions, interfering information, socially inappropriate behavior), shifting among rules, relating rules
contextual control (executive functions)
monitoring
working memory (executive functions)
- maintenance
- manipulation
brain regions supporting executive control
- dorsolateral prefrontal cortex
- ventrolateral prefrontal cortex
- posterior parietal cortex
- dorsomedial prefrontal cortex
- anterior congulate cortex
- orbifrontal cortex
- ventromedial cortex
- caudate nucleus
- putamen
Fuck this!
frontal dysexectutive syndrome (prefrontal lobe damage)
= damage to lateral prefrontal cortex
- difficulties in managing daily life (planning, interacting, …)
frontal disinhibition syndrome (prefrontal lobe damage)
= damage to ventral and medial regions
- difficulties in controlling movements, inapprobriate behavior (problems in initiating rules and approbriate behavior)
(ex. Phineas gage disease)
executive function of short- or long-term?
short term, suppressing/enhancing certain response
initiating new rules in the brain
happens in prefrontal cortex, with selective neurons (also involves basal ganglia)
initiating rules of behavior
in basal ganglia and prefrontal cortex
- object switch: basal ganglia
- object and rule switch: ventral basal ganglia, dorsal prefrontal cortex
inhibition of rules/behaviors
= suppression of unimportant information
halting trained behaviors, preventing interferences/irrelevant information, restraining socially inapprobriate actions, removing irrelevantt infromation from working memory
The oddball task
sequence of slighlty varying sings which have standard response, just target stimulus needs different response, which needs more time (inhibition of standard response)
-> triggers P300, activation in dorsolateral prefrontal cortex
shifting among rules - basic idea
goal change means rule change
The Wisconsin card sorting test
card sorting, evaluating rule on how to sort, get feedback, rule changes within the taks and current adaptation is needed
-> concerns prefrontal cortex; people which have damage in this are have a hard time switching the rules in-between, cannot adapt behavior quickly (paired-separation)
relating rules
- > creating complex mental models
- several low level judgments to make higher order judgment
- > higher order integration in frontopolar cortex (most anterior part of the prefrontal cortex)
hierarchy of brain regions in executive functions - basics
- anterior regions; complex associations (more demanding tasks)
-> supports functions related to implementing and modifying higher-order abstract goals - posterior regions; simple rule processing (stimulus response selection) (less demanding tasks)
-> support executive functions associated with selecting the approbirate motor action
(both are connected in the brain)
frontopolar cortex (executive functions)
tracking of (sub)goals, relation integration, infromation-seeking behavior
mid-dorsolateral PFC (executive functions)
task switching, categorization of sequences, complex stimulus-response, contingencies
premotor cortex (executive functions)
response selection, execution of simple actions, rule matching
posterior lateral (PFC)
selection of sequences of responses, categorization of sequences, rule learning
contextual control
= matching behavior to context
- allocating brain resources
- > dorsal medial prefrontal cortex and anterior cingulate cortex (inhibitigng incongruence)
The Stropp task
incongruent condition - mismatch (slower response)
-> increased activation of anterior cingulate cortex
concruent condition - match (faster response)
neutral condition - unrelated (faster response)
dorsal anterior cingulate (dorsal vs ventral region)
- dorsal = cognitive control
- ventral = emotion processes
working memory (+ brain region)
executive processing, maintaining and manipulating rules
- > in lateral prefrontal cortex (activity persits for entire delay period)
- > when manipulations need to be made that happens in the dorsolateral prefrontal cortex
Baddeley model (working memory)
- three capactiy-limited buffers
1. phonological loop; language
2. episodic buffer; episodic memory
3. visualspatial sketchpad; semantics - > for sound, multimodal/spatial/visual representation
Cowan model (working memory)
- two levels of working memory
1. activates lon-term memory representation (if not rehearsed -> rapid decay)
2. activates representaions within focus of executive control (only four items at a time)
structural connectivity (isotropic vs anisotropic)
- isotropic diffusion: diffusion same in every direction
- > molecules move from parts with higher to parts with lower concentration (restricted by cell walls, guiding in specific directions)
- anisotropic diffusion: different diffusion coefficients along different directions
- > cell walls and myelin impede such motion
structural connectivity (measurement))
measure diffusion in 3D space (quantified by tensor; direction of difussion, seeing restrictions of diffusion)
- > mean diffusion (overall amount of diffusion)
- > looking at fractional anisotropy; from 0 to 1
tactography
using direction to trace a line (seeing structures in the brain)
-> seeing main movement direction in voxel
functional connectivity
relationship between functional activity of different brain regions (how they are connected)
-> cannot measure all at ones, therfore split it in parts, taking average activation across all and see activation across all regions (done with MRI)
resting state connectivity
rest and think of nothing in particular
-> slow activation corresponds to functional irrelevant networks
brain tumors - 2 kinds
- tumor invading and destroying normal brain tissue (malignant)
- > causes neurological issues/cignitive miss-function
- tumor pressing on normal tissue and causing increased pressure within the brain (malign)
- > takes part of the brain over
onco-functional balance (brain tumor)
taking a lot away but not too much to perserve the functioning of the brain (when taking surgeon on brain)
fronto-aslant track (FAT)
connects posterior parts of the inferior frontal gyrus and the superior frontal gyrus
-> area concerns working memory and inhibtion
[the higher the mean diffusion activity, the lower the integrity of the trackt, the worse the performance of the task]
superior longitudinal fasciculus (SLF)
connects frontal and parietal regions; several branches with specific cogntivie functions
temporal pattern lesions
how left hemispheric tumor affects right hemisphere; adpatations can be made when there is time
-> slower growing tumors: higher capacity for distributed information processing bwteen modules in contralesional hemisphere
assortativity
high connectivity (highly connected nodes preferring to be connected to highly connected nodes) -> quicker information spread
disassortative
no high connectivity (not highly connected nodes preferring to be connected to not highly connected nodes)
default mode network
activated during rest, deactivated when task is done
frontal parietal network
activated for cogntiive flexibility tasks (working memory tasks)
