association cortex Flashcards
what is an association cortex?
everything that is not a primary sensory or primary motor area
what do association corticies do?
receive input from many areas and connect them in a way that wasn’t possible in the initial sensory area and usually generates a more meaningful response
what are the major association cortices?
Temporal (who/what pathway),Parietal (where/when pathway),Frontal
what functions does the temporal association cortex involve?
Visual forms, objects, textures
Auditory prosody, syntax
Polymodal/heteromodal - audio/ visual/somatic
what functions does the parietal association cortex involve?
Visuospatial awareness (attention) Visual motor transformations (intention) Somesthesis (body awareness)
what functions does the frontal association cortex involve?
spatial, object working memory
planning
withholding responses
what layer of cortex receives input from the thalamus?
layer 4 ( the granular layer)
what is the brainstem modulatory system?
Brainstem modulatory systems = 5HT, NE,
DA, etc.
what layer(s) do inputs go to in the cortex?
all layers
where do Outputs from layers 2 and 3 go?
other cortical areas - layer 3 cells are bigger, can go
to opposite hemisphere
where do outputs from layer 5 go?
subcortical structures like the striatum, superior colliculus,
pons, and tegmentum
where do outputs from layer 6 go?
the thalamus
what does damage from to the Temporal Association Areas / Ventral Stream lead to?
deficits in higher order perception of stimuli, but not necessarily the simple elements:
agnosia, achromatopsia, prosopagnosia, alexia, receptive aphasia, expressive aphasia apraxia,
what can result if the primary visual areas are damaged but the temporal association areas are spared?
a “ blindsight” can result and the patient doesn’t know that they can see
what is agnosia?
impaired object recognition
what is achromatopsia?
impaired color recognition
what is prosopagnosia?
impaired face recognition
what is alexia?
impaired word recognition
what is receptive aphasia?
impaired word interpretation. Input problem, ex. Wernicke’s
what is expressive aphasia?
impaired word usage. Output problem, ex. Broca’s
what is apraxia ?
object utilization / tool use deficits (impaired motor planning / ability to
carry out learned purposeful movements)
what is required to generate intention?
attention is required to generate intention
prefrontal cells encode the _______ and _______ of meaningful stimuli that can be used in a response.
location and time
*** what does the prefrontal cortex allow us to do?
METACOGNITION
*** what is the main function of the prefrontal cortex?
it supports the most meaningful selection of behavior to achieve desirable outcomes and avoid undesirable ones
**how does the prefrontal cortex do it’s function?
it facilitates metacognition through integration of sensory info and pausing the motor responses and monitoring of outcomes.
** what can happen in a prefrontal cortex lesion?
behavior changes, can’t control actions, problems withholding improper responses.
they are socially inappropriate,could also have motor, oculomotor or verbal problems
which common syndromes involve changes in the prefrontal cortex?
schizophrenia and ADHD
