Week 8 Higher Cortical Functions and Syndromes Flashcards Preview

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Flashcards in Week 8 Higher Cortical Functions and Syndromes Deck (18)
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1

Define higher cortical function.

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

2

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

-declarative memory: temporal lobe
-language production: prefrontal cortex (broca's)
-language comprehension: Wernicke's area
-visuospatial info: parietal cortex
-execution functions: prefrontal cortex

3

What are some skills and examples of hemispheric specialization?

-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

4

What are brain regions that are critical for memory formation?

-medial temporal lobe (hippocampus, parahippocampal gyrus)
-midline structures of the diencephalon (dorso-medial and ant. nucleus of the thalamus and mammilary bodies)

5

What are the three stages of memory processing?

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)

6

What is declarative memory?

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

7

What is non declarative memory?

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

8

What is anterograde amnesia?

-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

9

What is retrograde amnesia?

-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

10

Describe Korsakoff's syndrome.

-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

11

Describe the hemispheric lateralization of language and speech.

-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

12

Define aphasia.

impairment of language communication due to a brain dysfunction

13

Describe the features of Broca's aphasia.

-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

14

Describe the features of Wernicke's Aphasia.

-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

15

Describe hemispheric specialization of spatial processing and attention.

-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

16

Describe hemispatial neglect syndrome.

-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

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

-dorso-lateral prefrontal cortex
-orbito-frontal cortex
-anterior cingulate gyrus

18

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

-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

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