9/26 Association Cortices - Woodbury Flashcards
heteromodal association cortex
what are the unimodals?
what does heteromodal accomplish?
unimodal cortices deal with one modality of sense/action:
primary and secondary cortices for…
- motor
- somatosensory
- auditory
- visual
tertiary cortices are the ones that take the global view, help tie things together:
heteromodal association cortex
-
inferior parietal lobe: unified sensory precept
- supramarginal&angular gyri @ jx of temporal/parietal/occipital lobes
-
prefrontal cortex: executive function
- assess situation, weight options, determine output
- social cognition/personality
parietal heteromodal association cortex
goal
general steps of use
goal: create unified percept
- challenge is to only link the things that should be linked
general process:
- body senses discrete sensory inputs
-
inf parietal assembles the input, forms a percept
* limbic system feeds in - frontal lobes assess the percept and determine if action is warranted (and if so, what action)
- body executes the plan
synesthesia
aberrent binding of sensory information in parietal lobe
- show incr activity in parietal lobe, suggestive of “hyperbinding” of sensory inputs
effect: stimulation of one sensory system → perceived sensation in another system (non-stim)
- common: sounds/letters/numbers evoke visual color experience
parietal lobe lateralization
main fx
disorders produced by damage
symptoms of disorders
dominant hemisphere: closely assoc with language fx
- damage → Gerstmann’s syndrome
- math difficulty
- writing difficulty
- L/R confusion
- finger agnosia
non-dominant hemi: responsible for spatial awareness (intra/extrapersonal space, spatial orientation/awareness)
- damage → hemineglect
- loss of approp monitorying of intrapersonal/extrapersonal space
- extinction: each side capable of sensing, but deficient side OVERWHELMED on simultaneous stimulation (ex. R/L shoulder taps, finger wiggle)
connectome:
parietal and prefrontal
both the inferior parietal assoc cortex and the prefrontal cortex receive inputs from all unimodal association cortices
- connectomes are large white matter tracts connect association cortices
- information flows bidirectionally through connectomes
regions of frontal lobes
motor cortex → simple motor movments (single, fx units)
premotor cortex → complex motor movements (planned)
prefrontal cortex → no motor movements
diff parts of the frontal lobe perform many diff functions:
- motor movements
- language
- executive fx
- personality
- social interactions
- theory of mind
- dorsolateral PFC: executive fx
- orbitofrontal PFC: personality, emotional regulation, complex social interactions
- medial PFC (incl ant cigulate gyrus): emotions, social info processing, basic drives
orbitofrontal/medial PFC fx
PERSONALITY
- ethics
- morals
- social interactions
- emotions
theory of mind
concept of self
empathy
dorsolateral PFC fs
COGNITION
- executive fx
proactive-ness
looking forward in time
making/executing plans
adapting to new situations
maintaining focus
frontal lobe maturation
happens slowly over v long timecourse
- individual experience influences connections
executive fx
what is it?
regions involved
steps involved
engaging in current behavior to achieve a future goal
- requires looking ahead to see pos/neg outcomes of current action
- proper fx of PFC necessary, but not sufficient
- the longer the timeframe from behavior to reward, the more the frontal lobes are involved
steps involved
- initiation
- follow plan
- approp use of working memory
- suppress distractors
- introspection
- adaptation
executive dysfx
effect on each of the steps
- initiation → no motivation to change
- follow plan → improper sequencing of plan
- approp use of working memory → compromised working memory holds in place
- suppress distractors → compromised inhibition
- introspection → no progress monitoring
- adaptation → mental rigidity (stick with bad plan)
personality/behavior
role of brain regions
orbitofrontal PFC is the seat of personality
- most behavioral issues arise following damage to medial and Orbital Frontal Lobes (esp R hemi)
- damage comprimises the “filter” between impulse and action → Frontal Release Signs : actions that should be inhibited are not
- social interactions suffer, but “intellect” mostly makes it out OK
primary role of orbitofrontal PFC: inhibit actions
- influenced by reward and punishment
- learned social interactions
damage especially problematic because a lot of frontal lobe activity (plans/thoughts) are inhibited before they reach the level of consciousness, such that we’re not aware of them →→→ personality changes!!!
how do you damage teh orbitofrontal PFC?
coup contrecoup damage (closed head injuries) → personality changes, emergence of socially inapprop behaviors
utilization behavior
result of frontal lobe injury
patients behavior strongly influenced by objects in their environment
- end up acting out normally subconscious plans that should be suppressed
symptoms:
- show grasp reflex, interact with any object in environment
- repetitive activity driven EXTERNALLY, not internally
- route: see object → develop plans to interact → choose one plan → NO SUPPRESSION → act on plan
ex. flipping lights on/off, opening doors, etc
theory of the mind
skills bestowed
behavioral consequences
recognition that your thoughts are separate from thoughts of others
- NOT present in early life (pre-frontal lobe maturation)
- evident when a child starts to lie! → demonstration of understanding that parent’s knowledge base is different
skills:
- ability to imagine yourself in another’s place
- recognition of emotions assoc with facial exp
- recognition of emotions in speech/gestures
- empathy
consequences:
- failure to recognize how info is partitioned among individuals based on experiences/exposure (ex. Sam/Ralph and the hidden ball)
