The Central Nervous System

1. The Central Nervous System 9

2. Brain Function: Reflex Pathways in the Brain Figure 9-14

3. Brain Function: Cerebral Cortex • Three specializations • Sensory areas • Sensory input translated into perception • 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 Figure 9-15

5. Brain Function: Cerebral Lateralization Each lobe has special functions Figure 9-16

6. Brain Function: Sensory Information • Primary somatic sensory cortex • From skin, musculoskeletal system, and viscera • Somatosensory pathways • Touch • Temperature • Pain • Itch • Body position

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

8. 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

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

10. Brain Function: Behavioral State • Four modulatory systems • Adrenergic • Serotonergic • Sopaminergic • Cholinergic

11. Brain Function: Behavioral State

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

13. 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

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

15. 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

16. 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

17. 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

18. Brain Function: Memory Processing Memory is stored as memory traces Figure 9-22

19. Brain Function: Memory Alzheimer’s disease is a progressive disease of cognitive impairment characterized by memory loss

20. Brain Function: Language Cerebral processing of spoken and visual language Damage to Wernicke’s causes receptive aphasia Figure 9-23a

21. Brain Function: Language Damage to Broca’s area causes expressive aphasia Figure 9-23b

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

23. 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

24. 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

25. 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

26. 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