Week 8 Higher Cortical Functions and Syndromes Flashcards

1
Q

Define higher cortical function.

A

Higher cortical functions are processes by which primary sensory information is integrated into complex concepts and ideas that can be remembered and used to formulate a new action plan

  • example: memory, language, praxis, visuospatial info, execution fxns, verbal reasoning, attention, social behaviors
  • carried out in association cortices
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2
Q

List the higher cortical functions that can be localized to specific cortical regions.

A
  • declarative memory: temporal lobe
  • language production: prefrontal cortex (broca’s)
  • language comprehension: Wernicke’s area
  • visuospatial info: parietal cortex
  • execution functions: prefrontal cortex
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3
Q

What are some skills and examples of hemispheric specialization?

A
  • handedness
  • left hemisphere: language, reading & writing, calculations
  • right hemisphere: visuospatial ability, facial recognition, receptive and expressive rhythm and intonation of speech
  • music
  • appreciation of humor
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4
Q

What are brain regions that are critical for memory formation?

A
  • medial temporal lobe (hippocampus, parahippocampal gyrus)

- midline structures of the diencephalon (dorso-medial and ant. nucleus of the thalamus and mammilary bodies)

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5
Q

What are the three stages of memory processing?

A
  1. sensory memory
    - degrades in .5 to 3 secs
  2. short term memory
    - records info we attend to or think about (7-10 items)
    - recall info for 30secs-1min
    - can be enhanced by rehearsal or chunking
  3. long term memory
    - consolidation of info from short term to long term occurs within a few mins of being received
    - allows for continual storage of info for hrs to years
    - unlimited storage capacity
    - involves changes in synaptic efficacy (LTP or LTD, structural modification of dendritic spines and synaptogenesis)
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6
Q

What is declarative memory?

A

Conscious access to facts about our lives and the world around us

  • involves the medial temporal lobe including hippocampus, midline thalamus, mammilary bodies
  • eg. patient HM- anterograde amnesia
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7
Q

What is non declarative memory?

A

Knowledge that doesn’t require conscious access such as motor skills or cognitive skills, classical conditioning, problem solving
-involves diffuse brain regions including amygdala, cerebellum, frontal and parietal lobes

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8
Q

What is anterograde amnesia?

A
  • inability to convert new short term memories into long term so that info in short term memory is lost
  • can be part of global cognitive deficit like Alzhemier’s disease, or specific event like head trauma, stroke, or surgery that typically involves the hippocampus
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9
Q

What is retrograde amnesia?

A
  • loss of pre-existing memories before an injury or the onset of disease
  • can remember new facts but unable to recall things prior to some point in time
  • most likely involves areas of temporal lobe as well as other cortical areas where long term memories are stored
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10
Q

Describe Korsakoff’s syndrome.

A
  • a neurological disorder caused by a lack of thiamine (Vit B)
  • linked to chronic alcohol abuse, also can be by stroke, tumors and trauma
  • involves diencephalon, mostly the dorsomedial nucleus of thalamus and mammilary bodies
  • loss of declarative memory but preservation of non declarative memory
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11
Q

Describe the hemispheric lateralization of language and speech.

A
  • Wernike’s area in posterior portion of superior temporal lobe
  • Broca’s area: located inf/posterior frontal cortex
  • nondominant hemisphere is important in the recognition and production of the emotionally appropriate expression or tone of speech
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12
Q

Define aphasia.

A

impairment of language communication due to a brain dysfunction

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13
Q

Describe the features of Broca’s aphasia.

A
  • primary deficit in language output/production
  • language comprehension is intact
  • speech is effortful, delayed, and slow with a decrease in fluency of spontaneous speech
  • agrammatism: short/truncated phrases, can’t repeat phrases
  • typically caused by infarct of superior division of MCA or trauma to Broca’s area
  • often accompanied by paralysis of right upper limb
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14
Q

Describe the features of Wernicke’s Aphasia.

A
  • impairment of comprehension of spoken, written speech
  • fluent, spontaneous speech is normal but meaningless or caontains unintelligible content. can’t repeat words or phases
  • patient’s don’t respond appropriately to commands
  • typically caused by infarct of inferior division of MCA
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15
Q

Describe hemispheric specialization of spatial processing and attention.

A
  • left hemisphere responds to stimuli to right side of the body or in right visual field
  • right hemisphere responds to stimuli from both sides
  • lesions in right hemisphere lead to prominent and long lasting deficits in attention to contralteral side, while left hemisphere lesions results in mild deficits
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16
Q

Describe hemispatial neglect syndrome.

A
  • exhibit profound neglect for contralateral half of external world as well as contralateral side of their body
  • typically from lesions of the right parietal or frontal cortex due to sudden infarct or trauma
17
Q

What are the areas of the prefrontal cortex involved in executive function processing?

A
  • dorso-lateral prefrontal cortex
  • orbito-frontal cortex
  • anterior cingulate gyrus
18
Q

What is the dorso-lateral prefrontal circuit? What is an example of a clinical syndrome associated with the dorso-lateral prefrontal circuit?

A
  • originates from prefrontal cortex and projects to caudate
  • involved in working memory, planning ahead toward a defined goal, temporal ordering of events, judgement, abstract reasoning
  • Frontotemporal dementia (FTD): caused by degeneration of frontal lobe which may extend back to the temporal lobe- impaired reasoning, easily distracted, poor organizational strategies, socially inappropriate behavior