cerebral cortex
TRANSCRIPT
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Cerebral Cortex
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Layers• Most incoming
sensory signals: IV• Most output signals
leave cortex: V & VI• To brain stem and
SC: V• Fibers to thalamus:
VI• Intracortical
association functions: I,II,III
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Functional AreasStuttering & Laughter !
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Association Areas
• PRT Association area:
– Continous info about body spatial coordinates
– Language comprehension
– Initial processing of visual language (reading)
– Are for naming objects
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Specific Functional Areas
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Face Recognition
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Wernicke’s Area
• Plays the greatest single role of any part of the cerebral cortex for the higher comprehension levels of brain function that we call intelligence
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Cerebral Dominance?
• Dominant & nondominant hemispheres
• Categorical hemisphere • Sequential-analytic processes
– Language – Analytical reasoning
• Representational hemisphere • Visuospatial relations
– Identification of objects by their form– Recognition of faces– Recognition of musical themes
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Lesions of Representational & Categorical Hemispheres
• Lesions of categorical hemisphere: • Language disorders• Disturbed about their disability and often depressed
• Lesions of representational hemisphere:• No language disorders• Sometimes unconcerned and even euphoric!• Astereognosis—the inability to identify objects by feeling
them• Lesions of inferior parietal lobule cause unilateral
inattention and neglect • Inability to tell a story or make a joke
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Language
• Language is one of the fundamental bases of human intelligence and a key part of human culture
• Areas concerned:• Wernicke's area connected via Arcuate fasciculus to
Broca's area
• 2nd language• Broca’s area concerned is different from that
associated with native language• Children learning 2 languages simultaneously have the
same Broca’s area dealing with both languages
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• Two aspects:• Sensory
– Auditory input– Visual input
• Motor
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Language Disorders
• Aphasias• Abnormalities of language functions that are not due
to defects of vision or hearing or to motor paralysis• Caused by lesions in categorical hemisphere
» Most common cause is embolism or thrombosis of a cerebral blood vessel
– Wernicke’s Aphasia• Global Aphasia
– Motor Aphasia– Dysarthria
• Receptive and expressive aphasia*
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Language – Chair!
Type of Aphasia and Site of Lesion
Characteristic Naming Errors
Nonfluent (Broca’s area) "Tssair"
Fluent (Wernicke’s area) "Stool" or "choss" (neologism)
Fluent (areas 40, 41, and 42; conduction aphasia)
"Flair . . . no, swair . . . tair."
Anomic (angular gyrus) "I know what it is . . . I have a lot of them."
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Thoughts
• A “pattern” of stimulation of many parts of the nervous system at the same time, probably involving most importantly the cerebral cortex, thalamus, limbic system, and upper reticular formation of the brain stem. (Holistic theory)
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Memory
• Stored in brain by changing basic sensitivity of synaptic transmission b/w neurons as a result of previous neural activity
• New (facilitated) pathways - memory traces
• Once traces are established - they can be selectively activated by the thinking mind to reproduce the memories
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Classification
• Time-wise• Short-term
» Presynaptic ++ or --
• Intermediate long-term» Reversible chemical/structural changes (pre- or
postsynaptic)
• Long-term» Actual structural changes
• Functional • Declarative• Skill
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Classification
• Explicit or declarative memory • Associated with consciousness/awareness
• Implicit or nondeclarative memory • Does not involve awareness
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Hippocampus
• Storage of memories
• Lesion causes: • Anterograde & • Retrograde amnesia• Cannot establish new declarative memories• Can establish skill (reflexive) memories
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Strangeness & Familiarity
• Some parts of temporal lobes causes a change in interpretation of one's surroundings
• déjà vu phenomenon!
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