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
