Unit Eleven: The Nervous System: C. Motor and Integrative Neurophysiology

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Unit Eleven The Nervous System C. Motor and
Integrative Neurophysiology

• Chapter 57 Cerebral Cortex, Intellectual
• Functions of the Brain, Learning, and Memory

Guyton and Hall, Textbook of Medical Physiology,
12 edition
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Physiologic Anatomy of the Cerebral Cortex

• Three Types of Neurons
• Granular (stellate)
• Short axons
• Function as interneurons
• Excitatory with glutamate as neurotransmitter
• Inhibitory with GABA as neurotransmitter
• Found in the sensory areas of the cortex
• Found in association areas between sensory
• and motor areas

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Physiologic Anatomy of the Cerebral Cortex

• Three Types of Neurons
• b. Fusiform and Pyramidal
• Give rise to almost all output fibers from the
  cortex
• Pyramidal are larger and more numerous than
• fusiform
• Pyramidal-source of nerve fibers that go all the
  way
• to the spinal cord

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Physiologic Anatomy of the Cerebral Cortex
Fig. 57.1 Structure of the cerebral cortex,
showing I, molecular layer II,
external granular layer III, pyramidal layer
IV, internal granular layer V,
large pyramidal cell layer VI, layer of fusiform
or poly- morphic cells
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Physiologic Anatomy of the Cerebral Cortex

• Anatomical and Functional Relations of the
• Cerebral Cortex to the Thalamus and Other
• Lower Centers

Fig. 57.2 Areas of the cerebral cortex that
connect with specific portions
of the thalamus
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Functions of Specific Cortical Areas
Fig. 57.3 Functional areas of the human cerebral
cortex as determined by
electrical stimulation during neurological
surgery or examination
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Functions of Specific Cortical Areas

• Association Areas (see Fig. 57.4)
• Parieto-occipitotemporal association area
• Analysis of the spatial coordinates of the body
• Wernickes Area-important for language
• comprehension
• Angular gyrus area-needed for reading
• Area for naming objects

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Functions of Specific Cortical Areas

• Association Areas (see Fig. 57.4)
• Pre-frontal association area
• Brocas area-neural circuitary for word formation
• Limbic association area-behavior, emotions, and
• motivation
• d. Area for recognition of faces

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Functions of Specific Cortical Areas
Fig. 57.6
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Functions of Specific Cortical Areas

• Comprehensive Interpretative Function of
  Wernickes
• Area

Fig. 57.7
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Functions of Specific Cortical Areas

• Comprehensive Interpretative Function of
  Wernickes
• Area
• Angular gyrus-interpretation of visual
  information
• Concept of the Dominant Hemisphere
• Role of Language in the Function of Wernickes
  Area
• Functions of the Parieto-occipitotemporal Cortex
  in
• the Nondominate Hemisphere

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Functions of Specific Cortical Areas

• Higher Intellectual Functions of the
  Prefrontal
• Association Areas
• Decreased aggressiveness and inappropriate social
• behavior
• Inability to progress toward goals or carry
  through
• sequential thoughts
• Elaboration of thought-concept of a working
  memory
• Functions of a working memory

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Function of the Corpus Callosum

• Cutting the Corpus Callosum
• Blocks transfer of information from the dominant
• hemisphere to the motor cortex on the opposite
  side
• Prevents transfer of somatic and visual info from
  the
• right to left hemisphere
• Person would have two entirely separate conscious
• portions of the brain

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Thoughts, Consciousness, and Memory

• Memory-Roles of Synaptic Facilitation and
  Synaptic
• Inhibition
• Positive and negative memorysensitization or
• habituation of synaptic transmission
• Classification of memories
• Declarative
• Skill

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Thoughts, Consciousness, and Memory

• Declarative Memory- memory of the various
  details of
• integrated thought (i.e. memory of surroundings,
  
• time relationships, causes of experiences,
  meaning
• of an experience)
• Skill Memory- associated with motor
  activities based
• on previous learning (i.e. hitting a tennis
  ball)

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Thoughts, Consciousness, and Memory

• Short-Term Memory
• Intermediate Long-Term Memory
• Memory based on chemical changes in the
  presynaptic
• terminal or postsynaptic neuronal membrane

Fig. 57.9
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Thoughts, Consciousness, and Memory

• Molecular Mechanism of Intermediate Memory
• Mechanism of habituation-role of calcium channels
• Mechanism of facilitation-role of serotonin
  release
• and cAMP activity

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Thoughts, Consciousness, and Memory

• Long-Term Memory
• Structural changes in synapses during the
  development
• of long-term memory
• Increase in vesicle release site for secretion of
  
• transmitters
• Increase in number of transmitter vesicles
  released
• Increase in the number of presynaptic terminals
• Changes in the structure of dendritic spines that
• permit transmission of stronger signals

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Thoughts, Consciousness, and Memory

• Long-Term Memory
• Number of neurons and their connectivities change
  during
• learning
• Consolidation of Memory
• Rehearsal enhances the transference of short-term
  memory
• into long-term memory
• b. New memories are codified during consolidation

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Thoughts, Consciousness, and Memory

• Consolidation of Memory
• Roles of specific parts of the brain in the
  memory process
• Hippocampus promotes storage of memories
• Hippocampi not important in reflexive learning