Unit Eleven: The Nervous System: C 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

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

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

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

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

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

Functions of Specific Cortical Areas Association Areas (see Fig. 57.4) Parieto-occipitotemporal association area Analysis of the spatial coordinates of the body Wernicke’s Area-important for language comprehension Angular gyrus area-needed for reading Area for naming objects

Functions of Specific Cortical Areas Association Areas (see Fig. 57.4) Pre-frontal association area Broca’s area-neural circuitary for word formation Limbic association area-behavior, emotions, and motivation d. Area for recognition of faces

Functions of Specific Cortical Areas Fig. 57.6

Functions of Specific Cortical Areas Comprehensive Interpretative Function of Wernicke’s Area Fig. 57.7

Functions of Specific Cortical Areas Comprehensive Interpretative Function of Wernicke’s Area Angular gyrus-interpretation of visual information Concept of the Dominant Hemisphere Role of Language in the Function of Wernicke’s Area Functions of the Parieto-occipitotemporal Cortex in the Nondominate Hemisphere

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

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

Thoughts, Consciousness, and Memory Memory-Roles of Synaptic Facilitation and Synaptic Inhibition Positive and negative memory—sensitization or habituation of synaptic transmission Classification of memories Declarative Skill

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)

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

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

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

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

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