Chapter 26- Associative Cortices Flashcards
(23 cards)
which cortical layers are the most associated with associative areas ?
layers 2 and 3
what are ways associative cortices are different ?
they receive input, often processed, from other parts of the brain
what are the 3 different cortical laminations ?
1) paleocortex (oldest, small, 3 layers)
2) neocortex (newest, motor and sensory, 6 layers)
3) archicortex in the hippocampus, 4 layers, a bit more developed memory structure
what are the 3 lobes with association cortices ?
frontal, parietal, temporal
are association areas sensory or motor ?
they accomplish higher processing that integrates both
what is the parietal association area responsible for ?
attention
how is area 5 in parietal (association) different from premotor area ?
in area 5, processing info about space saw an increase in level of neuronal activity, and is always activated, always “paying attention”
however, in premotor, responds to stimuli to then do action. when there is action, activity goes up. no action- goes down. ceases when a movement will be produced
what happens if there’s a lesion in the parietal association area ?
contralateral neglect - problem with identifying part of the space.
which hemisphere is dominant for allocation of attention to space ?
right parietal
what happens with a right hemisphere lesion in parietal lobe ?
severe left neglect (because the right hemisphere is more important)
what happens with a left hemisphere lesion in parietal lobe ?
minimal right neglect (because the right hemisphere is more important)
what happens with a partial bilateral lesion in parietal lobe ?
severe right neglect
which side of the parietal lobe is activated when you’re paying attention to the left visual field ? right visual field ?
for left visual field- right
for right visual field- both
how can we see that the parietal lobe is an attention specific area ?
if we record electrode on a monkey, it will show that when neuronal firing rate is proportional to how much we pay attention to the target, and that cells fire a lot more when we’re paying attention
how does the parietal lobe aid the visual cortex ?
attention enhances neuronal response in visual cortex- a lot more spikes per second in the preferred orientation when you’re attending to the visual stimuli
which associative area is responsible for recognition ?
temporal
if we record in the temporal cortex of a monkey, when will you see a higher activation ?
a particular cell may react the highest to a complete view of the face in a certain angle
what will fMRI in temporal lobe during facial recognition show ?
an incredible % increase in signal change when face stimulus is presented
how are cortical columns in the temporal cortex organized ?
signal a particular object class or point of view, with relatively smooth transitions between object features across columns. (eg columns with facial recognition, and across columns goes from face turned left to face turned right)
which associative area is responsible for planning forward in time ?
prefrontal cortex
What is an experiment that would show that the prefrontal cortex is important in planning ? What is a clinical case?
1) Human subjects were presented with
a random sequence of circles, requiring a left-handed button press, and squares,
requiring a right-handed button press. Regions within lateral prefrontal cortex
were more active following events (either circles or squares) that violated repeating
patterns.
2) Phineas Gage
How are neurons activated during a delayed response task ?
The neuron begins firing more rapidly wnen the screen is lowered
and remains active throughout the delay period.
(D) When the screen is lowered and raised
but no food is presented, the same neuron is
less active.
what is a clear sign of frontal lobe trauma ?
not being able to sort by category
