Cerebral Cortex Flashcards

1
Q

what is the most highly developed in humans?

A

the cerebral cortex

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2
Q

what is the weight and thickness of the cerebral cortex?

A

half brains weight, roughly 1 cm thick but an area of 2 squared feet

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3
Q

what are the layers of the cerebral cortex?

A

neocortex (95%) 6 layers

paleocortex and archicortex are 3 layers and older phylogenetically

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4
Q

what are the most prevalent neuron cell type in the cortex?

A

pyramidal cells

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5
Q

pyramidal cells

A

principle projection neuron, long axons, dendritic spines,, have apical (to the top) and basal (horizontal) dendrites

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6
Q

dendritic spines

A

on pyramidal cells

  • thought to change shape as learning rates are increased (turn synapse efficacy)
  • poor spine development can lead to intellectual disabilites (autism, fragile X syndrome)
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7
Q

pyramidal cells

A

principle projection neuron, long axons, dendritic spines,, have apical (to the top) and basal (horizontal) dendrites, use glutamate and are excitatory

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8
Q

dendritic spines

A

on pyramidal cells

  • thought to change shape as learning rates are increased (turn synapse efficacy)
  • poor spine development can lead to intellectual disabilites (autism, fragile X syndrome)
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9
Q

Non pyramidal cells

A

cortical neurons that are not pyramidal

-short axons, interneurons, remain in cortex, diverse, inhibitory and release GABA

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10
Q

what are some examples of neocortical neurons (nonpyramidal)

A

basket, candle and bipolar cells

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11
Q

what are the layers of the neocortex?

A

top to bottom: molecular layer, external granular layer, external pyramidal layer, internal granule layer, internal pyramidal layer, multiform layer

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12
Q

what cell types are in the granular layer?

A

interneurons, small axons, bunch of small cells

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13
Q

is there white matter in the cortex?

A

yes

ex. line of gennari

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14
Q

does the neocortex show regional specialization??

A
YES
the somatosensory (postcentral gyrus) projects to nearby cortex so no need for a lot of long axons --> thinner neocortex whereas the motor cortex (precentral gyrus) needs to go down large tracks like the corticospinal tract so more pyramidal cells with long axons -->thicker cortex
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15
Q

does the neocortex show regional specialization??

A

YES
the somatosensory (postcentral gyrus) projects to nearby cortex so no need for a lot of long axons –> thinner neocortex whereas the motor cortex (precentral gyrus) needs to go down large tracks like the corticospinal tract so more pyramidal cells with long axons –>thicker cortex
***granular and agranular cortex is irregularly distributed

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16
Q

what is different from the broadmans areas that was once thought??

A

the volume of the cortex is constant, but their is variation among brodmann’s area sizes among individuals. **leads to variation of talents in individuals

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17
Q

what is different from the broadmans areas that was once thought??

A

the volume of the cortex is constant, but their is variation among brodmann’s area sizes among individuals (more like clouds of area). **leads to variation of talents in individuals

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18
Q

phineas gage

A

had a pole that went through the frontal lobe of his brain

  • *used to think that the brian worked as a whole but now they proved that parts of the cortex are specialized for different functions
    • people say phineas lost prefrontal cortex (ventromedial and a little dorsolateral)
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19
Q

phineas gage

A

had a pole that went through the frontal lobe of his brain

  • *used to think that the brian worked as a whole but now they proved that parts of the cortex are specialized for different functions
    • people say phineas lost prefrontal cortex
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20
Q

phineas gage

A

had a pole that went through the frontal lobe of his brain
**used to think that the brian worked as a whole but now they proved that parts of the cortex are specialized for different functions

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21
Q

what are the neocortical regions?

A

primary sensory (from the thalamic sensory relay nuclei), primary motor that gives rise to the cortical spinal tract, association areas and limbic area

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22
Q

sensory areas of the neocortex

A

-have a topographical organization that is distorted so that highly sensitive areas like the fingers have large cortical representations

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23
Q

parietal lobe function

A
  • primary somatosensory
  • initial processing of tactile and proprioceptive information
  • usually the left inferior parietal lobule is involved with language comprehension
  • rest of the parietal cortex has spatial orientation and directs attention
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24
Q

occipital lobe function

A
  • primary visual cortex in the banks of the calcarine sulcus

- visual assoication cortex involved in higher order visual processing

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25
Q

temporal lobe function

A
  • primary auditory cortex (transverse temporal gyri)
  • auditory association cortex
  • language comprehension on dominant side (wernikes)
  • higher order visual processing on non-dominant side
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26
Q

gustatory cortex

A

frontal lobe and insula

27
Q

vestibular cortex

A

superior temporal gyrus and posterior insula

28
Q

where is the primary olfactory cortex?

A

paleocortex, NOT neocortical

29
Q

frontal lobe

A

motor functions (corticospinal tract)

  • contains broca’s area (dominant hemisphere) that produces the spoken and written language
  • prefrontal cortex (basically the rest of the frontal lobe) has executive functions like personality, planning, foresight etc..
30
Q

frontal lobe

A

motor functions (corticospinal tract)

  • contains broca’s area (dominant hemisphere) that produces the spoken and written language
  • prefrontal cortex (basically the rest of the frontal lobe) has executive functions like personality, planning, foresight etc..
31
Q

what do association areas do?

A

little is known, mediate higher order mental functions

32
Q

what are the two types of association areas and what do they do?

A

unimodal association cortex adjacent to the primary area (ex. in occipital lobe the primary visual cortex (17) is surrounded by the 18,19 unimodal assoc cortex) and multimodal assocation cortex which is involved in higher order intellectual functions

33
Q

where is the multimodal association cortex?

A

inferior parietal lobule, much of the frontal and temporal lobes

34
Q

what are the two types of association areas and what do they do?

A

unimodal association cortex adjacent to the primary area (ex. in occipital lobe the primary visual cortex (17) is surrounded by the 18,19 unimodal assoc cortex) and multimodal assocation cortex which is involved in higher order intellectual functions
**animals have less association area and much more primary areas

35
Q

where is the multimodal association cortex?

A

inferior parietal lobule, much of the frontal and temporal lobes

36
Q

dominant hemisphere

A

the hemisphere that produces and comprehends language (usually left but sometimes right)

37
Q

right and left hemisphere asymmetries

A

cortical language is near the lateral sulcus that extends further posteriorly on the right because the planum temporale is larger on the left which is where language comprehension occurs

38
Q

if you stimulate the motor cortex near the mouth, it produces involuntary grunts, but stimulate other areas on the motor cortex, can move mouth but not speak or fail to find appropriate words, why?

A

because the motor strip is not just mouth movement, it has a language component

39
Q

if you stimulate the motor cortex near the mouth, it produces involuntary grunts, but stimulate other areas on the motor cortex, can move mouth but not speak or fail to find appropriate words, why?

A

because the motor strip is not just mouth movement, it has a language component

40
Q

brocas area

A

inferior frontal gyrus

usually nonefluent aphasia

41
Q

wernikes area

A

posterior part of the superior temporal gyrus (continuation into the planum temporale and inferior parietal lobule)
-usually efluent aphasia

42
Q

what is aphasia and what are the two types

A

inability to use languages
nonefluent (tan) - difficult to produce words, but can comprehend language
efluent - “word salad” - can write and speak, but really no linguistic content or meaning

43
Q

brocas area

A

inferior frontal gyrus
usually nonefluent aphasia if damaged because deprive motor areas of ability to generate language, but can still comprehend

44
Q

what is aphasia and what are the two types

A

inability to use languages
nonefluent (tan) - difficult to produce words, but can comprehend language
efluent - “word salad” - can write and speak, but really no linguistic content or meaning

45
Q

arcuate (superior longitudinal) fasciculus

A

interconnects brocca and wernickes areas. if you damage wernike, then brocas area remains unchecked
**leads to conduction aphasia if damage to arcuate fasic.

46
Q

prosody

A

“musical” or emotional content of speech that is in the non-dominant (usually right hemisphere)

47
Q

motor prosody vs. sensory prosody

A

motor prosody (generating emotion, authority etcc.) is in the inferior frontal gyrus of the right hemisphere (brocca) and sensory prosody (comprehending emotional content) is in the posterior temporoparietal region of the right hemispher (where wernikes is on the left)

48
Q

parietal cortex in terms of association areas

A

unimodal: visual assoc cortex, auditory assoc cortex and somatosensory cortex
* *damage can cause specific agnosias (inability to recognize objects and faces)
multimodal: near intraparietal sulcus, monitors body from the outside world (running from a tiger)

49
Q

intraparietal sulcus

A

separates superior and inferior parietal lobule

50
Q

right parietal lobe damage

A
  • patient has trouble with the left side of the body
  • thinks that it’s “not there”
  • *contralateral neglect
51
Q

right parietal lobe damage

A
  • patient has trouble with the left side of the body
  • thinks that it’s “not there”
  • *contralateral neglect
52
Q

left parietal lobe damage

A
  • needed for planning a movement based on sensory information
  • apraxias “lack of action”
  • ask patient to touch face and cant, but can scratch face
53
Q

prefrontal cortex

A
  • anterior to the corpus callosum
  • controls other cortical activities
  • interconnected withe the DMN of the thalamus (so similar things happen when DMN is damaged)
54
Q

prefrontal cortex

A
  • anterior to the corpus callosum
  • controls other cortical activities
  • interconnected withe the DMN of the thalamus (so similar things happen when DMN is damaged)
55
Q

what are the 2 types of prefrontal cortex?

A

dorsolateral (over the lateral convexity) that is interconnected with parietal assoc. areas that is important in working memory and ventromedial (in orbitofrontal area) that makes people impulsive when angry

56
Q

what are the 2 types of prefrontal cortex?

A

dorsolateral (over the lateral convexity) that is interconnected with parietal assoc. areas that is important in working memory and ventromedial (in orbitofrontal area) that makes people impulsive when angry

57
Q

what are the two main commisures that interconnect the cerebral hemispheres?

A

-corpus callosum and anterior commisure

58
Q

what does the anterior commisure interconnect?

A

temporal lobes through the anterior olfactory nuclei

59
Q

what does the corpus callosum not receive as far as fibers?

A

somatosensory and motor cortex hand area and parts of the primary visual field

60
Q

what does the corpus callosum not receive as far as fibers?

A

somatosensory and motor cortex hand area and parts of the primary visual field

61
Q

alexia without agraphia

A

**can write but cant read
if the left corpus callosum and parts of the left occipital lobe have a stroke then the language areas are intact and unaffected (broca and wernike) but because the intact right visual cortex cannot cross the corpus callosum to get to the language centers to “translate”

62
Q

alexia without agraphia

A

**can write but cant read
if the left corpus callosum and parts of the left occipital lobe have a stroke then the language areas are intact and unaffected (broca and wernike) but because the intact right visual cortex cannot cross the corpus callosum to get to the language centers to “translate”

63
Q

what are association bundles?

A

**like highways interconnecting areas on ONE hemisphere

can be u-shpaed or long like the arcuate fasic.