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Chapter 9b

Chapter 9b. The Central Nervous System. Brain Function: Reflex Pathways in the Brain . Sensory system (reflex). Feedback. Sensory input. Cognitive system (voluntary). Behavioral state system. Integration. CNS. Motor system. Output. Physiological response or behavior. Response.

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Chapter 9b

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  1. Chapter 9b The Central Nervous System

  2. Brain Function: Reflex Pathways in the Brain Sensorysystem(reflex) Feedback Sensoryinput Cognitivesystem(voluntary) Behavioralstate system Integration CNS Motorsystem Output Physiologicalresponse orbehavior Response (a) A simpleneural reflex (b) Behavioral state and cognition influence brain output. Figure 9-14

  3. Brain Function: Cerebral Cortex • From a functional viewpoint, it can be divided into three specializations • Sensory areas • Sensory input translated into perception (awareness) • Motor areas • Direct skeletal muscle movement • Association areas • Integrate information from sensory and motor areas • Can direct voluntary behaviors

  4. Brain Function: Functional Areas of the Cerebral Cortex FRONTAL LOBE PARIETAL LOBE Primary somatic sensory cortex Primary motor cortex Skeletalmusclemovement Motor associationarea (premotor cortex) Sensory association area OCCIPITAL LOBE Visualassociationarea Prefrontalassociationarea Vision Visualcortex Taste Gustatory cortex Smell Olfactory cortex Auditoryassociation area Auditorycortex Hearing TEMPORAL LOBE Figure 9-15

  5. RIGHT HAND LEFT HAND Prefrontalcortex Prefrontalcortex Speechcenter COR P U S C A L L OS U M Analysisby touch Writing Auditorycortex(right ear) Auditorycortex(left ear) Spatialvisualizationand analysis Generalinterpretivecenter(language andmathematicalcalculation) Visual cortex(left visual field) Visual cortex(right visual field) LEFTHEMISPHERE RIGHTHEMISPHERE Brain Function: Cerebral Lateralization • Each lobe has special functions Figure 9-16

  6. Split Brain Split brain video

  7. Brain Function: Sensory Information • Primary somatic sensory cortex • Termination point of pathways from skin, musculoskeletal system, and viscera • Somatosensory pathways • Touch • Temperature • Pain • Itch • Body position

  8. Homunculus - Motor and Sensory

  9. Brain Function: Sensory Information • Special senses have devoted regions • Visual cortex • Auditory cortex • Olfactory cortex • Gustatory cortex • Processed into perception

  10. Brain Function: Motor System • Three major types • Skeletal muscle movement • Somatic motor division • Neuroendocrine signals • Hypothalamus and adrenal medulla • Visceral responses • Autonomic division • Voluntary movement • Primary motor cortex and motor association areas

  11. Brain Function: Behavioral State • Modulator of sensory and cognitive processes • Neurons collectively known as diffuse modulatory systems • Originate in reticular formation in brain stem

  12. Brain Function: Behavioral State • Four diffuse modulatory systems • Noradrenergic • Serotonergic • Dopaminergic • Cholinergic

  13. Brain Function: Behavioral State Table 9-3

  14. Brain Function: PET Scan of the Brain at Work Figure 9-17

  15. Brain Function: Perception Figure 9-18

  16. Brain Function: Diffuse Modulatory Systems Modulate Brain Function To basalnuclei Thalamus Raphenuclei Hypothalamus Cerebellum Locus coeruleus (a) Norepinephrine (b) Serotonin Figure 9-19a-b

  17. Brain Function: Diffuse Modulatory Systems Modulate Brain Function Cingulategyrus Prefrontalcortex To basalnuclei Substantianigra Fornix Ventraltegmental area Pontinenuclei (d) Acetylcholine (c) Dopamine Figure 9-19c-d

  18. Brain Function: States of Arousal • Electroencephalograms (EEGs) and the sleep cycle • Reticular activating system keeps “conscious brain” awake Figure 9-20a

  19. Brain Function: Sleep • Four stages with two major phases • Slow-wave sleep • Adjust body without conscious commands • REM sleep • Brain activity inhibits motor neurons to skeletal muscle, paralyzing them • Dreaming takes place • Circadian rhythm • Suprachiasmatic nucleus

  20. Brain Function: Emotion and Motivation • The link between emotions and physiological functions Figure 9-21

  21. Brain Function: Motivation • Defined as internal signals that shape voluntary behavior • Some states known as drives • Work with autonomic and endocrine responses • Motivated behaviors stop • Satiety

  22. Brain Function: Moods • Similar to emotions but longer-lasting • Mood disorders • Fourth leading cause of illness worldwide today • Depression • Sleep and appetite disturbances • Alteration of mood and libido • Antidepressant drugs alter synaptic transmission

  23. Brain Function: Learning and Memory • Learning has two broad types • Associative • Nonassociative • Habituation • Sensitization • Memory has several types • Short-term and long-term • Reflexive and declarative

  24. Brain Function: Memory Processing Figure 9-22

  25. Brain Function: Long-Term Memory Table 9-4

  26. Brain Function: Language • Cerebral processing of spoken and visual language • Damage to Wernicke’scauses receptive aphasia Motorcortex Broca’sarea Wernicke’sarea Visualcortex Readwords (a) Speaking a written word Figure 9-23a

  27. Brain Function: Language • Damage to Broca’sarea causes expressive aphasia Motorcortex Broca’sarea Hearwords Auditorycortex Wernicke’sarea (b) Speaking a heard word Figure 9-23b

  28. Brain Function: Personality • Combination of experience and inheritance • Schizophrenia • Both genetic and environmental basis

  29. Summary • Emergent properties • Evolution of CNS • Anatomy of CNS • Neural tube, gray and white matter, tracts, meninges, and cranium • Choroid plexus, CSF, and blood-brain barrier • Spinal cord • Spinal nerves, dorsal root, dorsal root ganglia, ventral roots, ascending tracts, descending tracts, propriospinal tracts, and spinal reflexes

  30. Summary: Brain • Brain stem, cranial nerves, reticular formation, medulla oblongata, somatosensory tract, corticospinal tract, and pyramid • Pons, midbrain, cerebellum, diencephalon, thalamus, hypothalamus, pituitary gland, pineal gland, and corpus callosum • Frontal, parietal, temporal, and occipital lobes • Cerebral cortex, basal ganglia, limbic system, amygdala, cingulate gyrus, and hippocampus

  31. Summary: Brain Function • Sensory system, cognitive system, and behavioral state system • Sensory areas, motor areas, association areas, and cerebral lateralization • Primary somatic sensory cortex, visual cortex, auditory cortex, gustatory cortex, and olfactory cortex • Association areas and perception

  32. Summary: Brain Function (continued) • Primary motor cortex, motor association area, behavioral state system, diffuse modulatory systems, and reticular activating system • Circadian rhythms, sleep, motivation, and moods • Learning, habituation, memory, and consolidation

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