Cerebral Cortex III

Question 1

How are different cortical areas connected together

Answer 1

Patterns of connections between lower level and higher order sensory areas

Question 2

where do feedforward projections originate

Answer 2

From superficial layers and project to layer iv

Question 3

where do feedback projections originate

Answer 3

In deep layers and avoid layer 4

Question 4

describe example pathway = feedforward ascending, v1,v2

Answer 4

In v1 = Feedforward projections = originate in pyramidal superficial layers = layers 2 and 3
Axons enter white matter = down through cortex and go over to next region = v2
Terminate in layer 4 = received feedforward projections - to Stellate cells

Question 5

describe example pathway = feedback descending, v1,v2

Answer 5

Originate in layer 6 of v2
Then go to v1 = layer 6 or 1

Question 6

describe receptive fields in somatic sensory association cortex vs primary somatic sensory cortex = gen

Answer 6

Larger than in primary somatic sensory cortex = get more complex as go up hierarchy

Question 7

describe receptive fields in somatic sensory association cortex vs primary somatic sensory cortex = in primary

Answer 7

Rfs in primary sensory area = larger
Rfs change a lot in cortex bc convergence and divergence = gets all mixed together
Larger and respond to more complex stimuli
Neuron in SI = rf corresponds to contralateral finger tip

Question 8

describe receptive fields in somatic sensory association cortex vs primary somatic sensory cortex = in area 5

Answer 8

rf corresponds to all teh fingers = much larger
So unified = like objects, integrate rfs so neuron can interpret what is going on in whole hand

Question 9

Describe what happens as neurons rf gets larger = neuron that responds to sensory stimulation of either hand

Answer 9

Higher order neurons on both sides = communicate with each other
Somatic sensory = crosses over
As rfs get larger = more synthesized sensory perception but lose fine detail but have fine discrimination and. Sense of objects bc all tehse sensory areas work together = communicate = feedback and feedforward, integrate lower and higher level processing in assembled complex way

Question 10

describe neuron most sensitive to a stimulus moving in a specific direction

Answer 10

Neuron Responds to stroking hand in one direction only
Integrates many small rfs
Direction specific

Question 11

describe the 2 stream fo processing

Answer 11

2 stream of sensory processing = for all sensory systems =
Dorsal sensory association areas and ventral association areas
Things converge together = diff sensory modalities integrate together, important for unifying sensory modulates —> unified perception of world

Question 12

describe dorsal pathway

Answer 12

Dorsal sensory association areas = enable sensory info to used To direct action
Where- uses sensory info to guide movement - like grab obejct

Question 13

describe ventral pathway

Answer 13

Ventral sensory association areas = involved in object recognition and memory
What = actual conscious perception

Question 14

What are/describe multimodal association cortex

Answer 14

areas = not specific to one modality
Puts together the diff sensory modulates into a unified perception and mediates the most complex aspects of human cognition
Small in rat brain, huge in humans
Motor/cognitive areas
Areas = important for language and attention

Question 15

describe frontal association cortex

Answer 15

Prefrontal cortex
Related to action, large in humans
Planning and decision making

Question 16

describe posterior multimodal association cortex

Answer 16

Convergence of sensory modalities = unified sensory perception
Used to guide behaviour

Question 17

are the 2 hemispheres the same

Answer 17

NOOOO
Functions are lateralized =
Localize functions in specific sides/areas, more energy efficient if grouped together

Question 18

describe left hemisphere functions

Answer 18

Language
Analytical
Mathematical thinking

Question 19

describe right hemisphere functions

Answer 19

Spatial reasoning
Orienting in space

Question 20

where is language

Answer 20

In most people = language lateralized to left hemisphere -90% of ppl
First thing that showed that teh 2 hemispheres were different

Question 21

describe lesion to left hemisphere posterior association cortex

Answer 21

Can result in aphasia = loss of language function
Wernickes aphasia= very talkative but do not make sense = gibberish, cannot understand words, can’t translate thoughts to words, sounds of words and meanings are dysfunctional
Lesion in higher order sensory areas close to auditory processing areas = wernickes area, lesion in higher level association cortex, in vicinity of primary auditory cortex

Question 22

describe left side lesions to more rostral regions of cortex

Answer 22

can result in brocas aphasia
Can understand but cannot talk = very slow, leave out words, issue with thoughts of language—> actual motor execution
Ventral region frontal lobe = close to areas controlling face but not actual issues with muscles

Question 23

what is arcuate fasiculus

Answer 23

Connects the 2 regions - model of language, way more complicated
Sounds translated into meanings of words in wernickes areas then info transmitted to Broca’s area = meaning translated to execution of language

Question 24

what is right hemisphere language involved in

Answer 24

Involved in aspects of language that give it emotional context=
Voice has diff intonations/emotions behind it and musicality

Question 25

describe Lesions on right hemisphere resulting in deficits for language/langauge processing

Answer 25

Areas roughly equivalent to brocas and wernickes areas in right hemisphere = so if stroke in right hemisphere near tehse = can cause deficits in understanding intonations of other peoples langauge (can’t understand intonation)- wernickes or deficits in executing intonation and musicality = Broca’s area