L28: Association Cortex

Question 1

Define Association Cortex

Answer 1

Everything in btw primary sensory areas, primary motor and premotor areas. Association areas literally receive inputs from multiple areas and tie them together in some manner that was not possible and usu generate more meaningful responses.

Question 2

T/F: All neocortical association areas have at least 5 layers (most have 6).

Answer 2

True

Question 3

What’s the significance of knowing what cells are in each of the neocortical layers and where they receive inputs (e.g. thalamus, brainstem)?

Answer 3

If you know layers, you can predict symptoms based on pathology superficially vs deeper problems.

Question 4

What is the Mirror Neuron System?

Answer 4

-“watch & learn”

for ex: show animal tongue & the animal sees tongue & learns how to protrude tongue as well.

Question 5

What happens when there’s damage to temporal association areas (e.g. ventral stream/grasp area)?

Answer 5

you will have impaired higher order perception of stimuli

• agnosia: impaired object recognition
• achromatopsia: impaired color recognition
• prosopagnosia: impaired face recognition
• alexia: impaired word recognition
• receptive aphasia: impaired word interpretation
• expressive aphasia: impaired word usage
• apraxia: impaired object utilization/tool use

Question 6

How are symptoms different from when primary visual areas are damaged vs temporal association areas?

Answer 6

If primary visual areas are damaged, then pt might have “blind sight” in which patient is not aware that they CAN see, but they can. This suggests that awareness involves communication btw temporal association areas & primary visual areas.

Question 7

What happens when there’s damage to parietal association areas?

Answer 7

• breakdown of “where” pathway/dorsal stream
• hemineglect
• inattention
• impaired spatial accuracy

*symptoms depend on which hemisphere of the parietal association fibers are damaged
right hemisphere lesion -> severe left neglect
left hemisphere lesion -> minimal right neglect
partial bilateral lesion -> severe right neglect

Question 8

What are the functions of the prefrontal association areas?

Answer 8

It supports most meaningful selection of behavior to achieve desirable outcomes, avoid undesirable ones; does so thru integration of sensory info & pausing the motor responses & monitoring of outcomes = “metacognition” & plays a role in working memory

Question 9

What happens when there’s damage to prefrontal cortex association areas?

Answer 9

• effects depend on precise regions

- could lead to emotional, cognitive, motor, oculomotor, verbal, or problems withholding improper responses

Question 10

Patients with schizophrenia and ADHD are syndromes w/ deficits in working memory & planning -could be due to problems in which part of the brain?

Answer 10

prefrontal cortex

Question 11

Describe the general functions of these areas in the prefrontal cortex:

• area 9
• area 46
• area 47/12

Answer 11

• area 9 –> planning, monitoring sequential actions or words
• area 46 –> spatial working memory
• area 47/12 –> verbal and object working memory

Question 12

Where will you find the following:

a) “facial recognition neurons”
b) “planning neurons”
c) “attention neurons”
d) “reach neurons”
e) “grasp neurons”
f) “mirror neurons”
g) “instructed delay neurons”

Answer 12

a) “facial recognition neurons” –temporal assoc
b) “planning neurons” —area 9 of prefrontal assoc
c) “attention neurons” –parietal assoc
d) “reach neurons” –parietal assoc
e) “grasp neurons” –temporal
f) “mirror neurons” – ventral premotor area
g) “instructed delay neurons” – prefrontal