Cognitive Processes & Association Cortex Flashcards

1
Q

Define cognition:

A

Our “internal life” (perception, attention, memory, language, emotion, planning & consciousness)

  • Involves integration of many kinds of information
  • –Produces a perceptual “whole”
  • Guides the choice of appropriate behaviors (ex: to achieve a specific goal)
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2
Q

What is the default network involved in?

A

-Daydreaming or mind wandering
-Autobiographical memories
-Envisioning the future
-Moral decisions
Contrasts with the “task-positive network” active when performing specific tasks
(this is still a form of cognition)

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3
Q

When might the default network be disturbed/less active?

A

In mental illness:

  • Depression
  • Obsessive-compulsive disorder
  • Schizophrenia
  • Autism
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4
Q

What areas are more active in the default network?

A
  • Dorsolateral Prefrontal
  • Rostrolateral Temporal
  • Posterior Parietal
  • Posterior Cingulate/Precuneus
  • Medial Prefrontal
  • Medial Temporal
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5
Q

When are the active parts in the default network less active?

A

When you are doing a task.

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6
Q

What are the primary areas of the cortex?

A
  1. Primary motor cortex
  2. Primary auditory cortex
  3. Primary somatosensory cortex
  4. Primary visual cortex
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7
Q

When can cognition also occur?

A

Between stimulus and response. (ex: during default network we are less aware of sounds, ex: waiting for the bus and being aware of it’s presence, planning for the bus by pulling out your umbrella and pulling out the bus pass, waiting for other people to enter the bus first (appropriate social behavior))

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8
Q

What is the association cortex?

A
  • “Not Primary” cortex
  • –Unimodal: integrates information within one sensory modality (seeing ball)
  • –Multimodal: integrates information across sensory modalities and from other sources (memory, emotion) (hearing ball hit ground and seeing it bounce)
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9
Q

What are the parts of the unimodal association cortex?

A
  1. Premotor cortex
  2. Somatosensory association cortex
  3. Visual association cortex
  4. Auditory association cortex
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10
Q

How does information flow through the association cortex?

A

Hierarchy of projections to carry out an appropriate behavioral response to a stimulus:

  1. Primary sensory cortex
  2. Unimodal
  3. Multimodal
  4. Premotor cortex
  5. Motor cortex
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11
Q

What alters information flow through the association cortexes?

A
  • Extensive feedback projections

- “Shortcuts” between areas

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12
Q

What cell types are prevalent in 2/3/5/6 cortex layer?

A

Pyramidal cells - excitatory cells

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13
Q

What cell types are most prevalent in 4th cortex layer?

A

Stellate cells - excitatory cells (star-shaped, dendritic trees)

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14
Q

What are the main inputs to the cortex?

A
  1. Thalamus
  2. Other cortical regions
  3. Brainstem nuclei (modulatory)
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15
Q

What are the three main functions of Association Cortex?

A
  1. Integrate input form different modalities
  2. Mediate “Internal” cognition
  3. Mediate between sensory inputs and the appropriate behavioral output
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16
Q

What doe the parietal association cortex do in Nondominant hemisphere?

A
  1. Attention
  2. Visuospatial localization: searching or reaching for an object
  3. Spatial relationships: binding the elements of a visual scene together into a single image
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17
Q

What does the parietal association cortex do in Dominant hemisphere?

A
  1. Skilled movments
  2. Right-left orientation
    (this hemisphere is specialized for language)
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18
Q

What can damage in the posterior parietal cortex cause?

A
  1. Spatial neglect (nondominant hemisphere)

2. Motor apraxias (dominant hemisphere)

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19
Q

What is spatial neglect?

A

Failure to acknowledge half of the world

  • -Sensory systems are intact
  • -Can apply to
  • —Environment
  • —Body
  • —Memories and visualizations
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20
Q

When does spatial neglect commonly occur?

A

Occurs in about half of right-hemisphere strokes (left visual field is ignored)

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21
Q

What does motor apraxia cause?

A
  • Loss of ability to perform skilled motions

- Sensory and motor systems are intact

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22
Q

What happens in ideomotor apraxia?

A

Patient may not be:

  • able to perform action in daily life, depending on severity
  • aware of the deficit
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23
Q

What indicates damage in ideomotor apraxia?

A

Use of hand in place of imaginary tool.

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24
Q

What are other apraxias?

A

Inabilty:
-To make specific facial movements (orofacial)
-To sequence actions (ideational)
These involve other parts of the brain

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25
Q

How do face neurons work?

A
  • No ‘grandmother’ neuron
  • Represented through population coding:
  • –Each neuron responds to particular features
  • –Together, groups of these neurons are used to build a unified image
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26
Q

What are deficits in recognition?

A

Agnosias

  • Inability to recognize or identify objects even though sensory systems are working normally
  • Damage to several cortical areas can produce agnosia of different types
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27
Q

What is prosopagnosia?

A

Inability to recognize faces [caused by bilateral lesion of inferior temporal cortex]

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28
Q

What is visual agnosia?

A

Inability to recognize an object by sight (recognition by other senses remains intact) [caused by damage to unimodal visual cortex]

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29
Q

What is astereognosia?

A

Inability to recognize an object by touch alone [caused by damage to unimodal somatosensory cortex]

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30
Q

What is associative visual agnosia?

A

Can identify but not name [Caused by damage to the posterior parietal cortex - ex: know its used to comb hair but cannot realize its a comb]

31
Q

What does damage to prefrontal cortex cause?

A
  • Impaired restraint (loss of impulse control)
  • Socially inappropriate behavior
  • Disordered thought
  • Inability to plan
  • Perseveration (reputation of behavior)
  • Inability to use information to guide behavior (cognitive inflexibility)
32
Q

What is the cortex like at birth?

A
  • Distinct sensory, motor and prefrontal networks (not yet integrated)
  • A rudimentary default network
  • We are particularly sensitive to damage from stressors in infancy and early childhood
33
Q

What happens in first year of life?

A

Rapid cortex development

34
Q

How many layers are there in the cortex?

A

6

35
Q

Why does primary visual cortex have a large layer 4?

A

It receives much information from other areas (thalamus)

36
Q

What does primary motor cortex slides look like?

A

Very narrow layer 4 and very wide layer 5!

37
Q

What is in layer five of primary motor cortex?

A

Beitz cells - many projections to subcortical regions

38
Q

What are the main outputs of the cortex?

A
  • Other cortical regions

- Subcortical structures (including feedback to thalamus)

39
Q

What type of cortex has a higher density of croticocortical connections?

A

Association cortex

40
Q

Where do modulatory inputs to the association and primary cortexes come from?

A
  • Thalamus

- Brainstem

41
Q

What is the function of the parietal cortex?

A

Visual attention, localization, spatial relationships, motor programs

42
Q

What is the function of the limbic cortex?

A

Association & Memory

43
Q

What is the function of the temporal cortex?

A

Recognition and object identification, language

44
Q

What is the function of the prefrontal cortex?

A

Planning and decision making (executive function), working memory

45
Q

Where is attention/selective attention localized? What group is this area working improperly in?

A

Posterior (inferolateral) parietal cortex. [Deciding what is important and what isn’t]
-Schizophrenia

46
Q

What is the stroop test and what is it used for?

A

-Have to look at a word and say the color of its font
People with damage to the posterior partietal will not be able to tell you what the color of the word is, they will just say the word.

47
Q

What is apraxia?

A

Difficulty in motor planning and performing tasks

48
Q

What is ataxia?

A

Lack of coordination in movements.

49
Q

What is spatial neglect?

A

Failure to acknowledge half of the world.

  • Sensory systems are intact
  • Can apply to:
  • –Environment
  • –Body
  • –Memories and visualizations
50
Q

When does spatial neglect normally occur/what patients?

A

Half of right-hemisphere strokes –> right hemisphere attends to left visual field but both hemispheres attend to right visual field

51
Q

What part of the posterior parietal cortex attends to the right visual field?

A

Both cortices!

52
Q

What part of the posterior parietal cortex attends to the left visual field?

A

Right cortex

53
Q

Where is the damage that causes most motor apraxias?

A

Interparietal sulcus

54
Q

What is ideomotor apraxia?

A
  • Involves gestures (eg waving goodbye) or the use of tools
  • Many tools used in daily life:
  • –Kitchen utensils
  • –Toothbrush
  • –Broom
  • –Scissors
  • –Keys
55
Q

How can you test for Ideomotor Apraxia clinically?

A
  • Ask patients to pantomime use of imaginary tools
  • Imitate the action
  • Use a actual tool
56
Q

What does the superior temporal sulcus do?

A
  • Language

- Social attention

57
Q

What does the inferior temporal cortex (includes deep structures) do?

A

-Recognition (ex: faces)

58
Q

The are specific neurons in the inferior temporal cortex that recognize. ..

A

faces! (and profiles of faces!)

59
Q

What other things might have specialized recognition regions in the brain?

A

Body parts & places

60
Q

What is finger agnosia?

A
  • Can’t tell which finger is which
  • Damage to angular gyrus of dominant parietal cortex
  • Gerstmann syndrome
61
Q

What is Gerstmann syndrome?

A

Finger agnosia, acalculia (inability to calculate), agraphia (inability to graph), and right-left confusion

62
Q

What are the main functions of the prefrontal cortex?

A
  • Executive function
  • –Planning
  • –Making decisions
  • –Purposeful action
  • –Sequencing behaviors over time
  • –Selection and execution of appropriate behavior
  • Working memory
63
Q

What does she think is interesting about Phineas Gage?

A

He must have had some recovery of the prefrontal cortex in order to plan & show up on time at his job as a stagecoach and to make it to Africa, etc.

64
Q

What is the Wisconsin Card Sorting Test? What does it test?

A

-Patient only told if their response is right or wrong.
-At some point, the rule changes –> people with prefrontal damage have a lot of trouble with adjusting to this new rule
-It tests prefrontal cortical function!
{shape, color and number of objects different on each card}

65
Q

What changes occur in the cortex during development?

A
  • Synaptic density
  • Myelination
  • Gray matter thickness
66
Q

Test: Identify common faces (what area?)

A

Inferior Temporal Cortex

67
Q

What does stroop test indicate?

A

Parietal association cortex

68
Q

Have patient draw a picture or describe a room:

A

This indicates posterior parietal cortex damage - hemispatial neglect.

69
Q

How does the brain change in MRI from 2 weeks to 2 years?

A
  • 2 weeks - very amorphous

- By 2 years, more development of myelination & pathways (axons) - more organization of synapses and tracts

70
Q

What areas mature faster than other areas of the brain?

A

Mature first - Sensorimotor
Second - Less-connected (unimodal) association areas
Last - Highly-connected prefrontal, posterior parietal last

71
Q

What areas of the brain are usually the first to degenerate?

A

The last areas to mature :(

72
Q

What matures sooner, local or long-range connections?

A

Local connections, then long-range connections later

73
Q

What can deregulation of the brain in Alzheimer’s cause?

A

Behavior problems

Inability to adapt

74
Q

How does gray matter thickness change through childhood?

A

It gets thicker until age 5. Then it gets thinner as your age and become more mature.
-As you age, myelination is also increasing which may be causing part of the gray matter shrinkage