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  1. 1. The Nervous System <ul><li>Major division - Central vs. Peripheral </li></ul><ul><li>Central or CNS- brain and spinal cord </li></ul><ul><li>Peripheral- nerves connecting CNS to muscles and organs </li></ul>Central Nervous System Peripheral Nervous System
  2. 2. Peripheral Nervous System <ul><li>3 kinds of neurons connect CNS to the body </li></ul><ul><ul><li>sensory </li></ul></ul><ul><ul><li>motor </li></ul></ul><ul><ul><li>interneurons </li></ul></ul><ul><li>Motor - CNS to muscles and organs </li></ul><ul><li>Sensory - sensory receptors to CNS </li></ul><ul><li>Interneurons: Connections Within CNS </li></ul>Spinal Cord Brain Nerves
  3. 3. Peripheral Nervous System S k e l e t a l ( S o m a t i c ) S y m p a t h e t i c P a r a s y m p a t h e t i c A u t o n o m i c P e r i p h e r a l N e r v o u s S y s t e m
  4. 4. Somatic System <ul><li>Nerves to/from spinal cord </li></ul><ul><ul><li>control muscle movements </li></ul></ul><ul><ul><li>somatosensory inputs </li></ul></ul><ul><li>Both Voluntary and reflex movements </li></ul><ul><li>Skeletal Reflexes </li></ul><ul><ul><li>simplest is spinal reflex arc </li></ul></ul>Muscle Motor Neuron Interneuron Skin receptors Sensory Neuron Brain
  5. 5. Autonomic System <ul><li>Two divisions: </li></ul><ul><ul><li>sympathetic </li></ul></ul><ul><ul><li>Parasympatheitic </li></ul></ul><ul><li>Control involuntary functions </li></ul><ul><ul><li>heartbeat </li></ul></ul><ul><ul><li>blood pressure </li></ul></ul><ul><ul><li>respiration </li></ul></ul><ul><ul><li>perspiration </li></ul></ul><ul><ul><li>digestion </li></ul></ul><ul><li>Can be influenced by thought and emotion </li></ul>
  6. 6. Sympathetic <ul><li>“ Fight or flight” response </li></ul><ul><li>Release adrenaline and noradrenaline </li></ul><ul><li>Increases heart rate and blood pressure </li></ul><ul><li>Increases blood flow to skeletal muscles </li></ul><ul><li>Inhibits digestive functions </li></ul>CENTRAL NERVOUS SYSTEM Brain Spinal cord SYMPATHETIC Dilates pupil Stimulates salivation Relaxes bronchi Accelerates heartbeat Inhibits activity Stimulates glucose Secretion of adrenaline, nonadrenaline Relaxes bladder Stimulates ejaculation in male Sympathetic ganglia Salivary glands Lungs Heart Stomach Pancreas Liver Adrenal gland Kidney
  7. 7. Parasympathetic <ul><li>“ Rest and digest ” system </li></ul><ul><li>Calms body to conserve and maintain energy </li></ul><ul><li>Lowers heartbeat, breathing rate, blood pressure </li></ul>CENTRAL NERVOUS SYSTEM Brain PARASYMPATHETIC Spinal cord Stimulates salivation Constricts bronchi Slows heartbeat Stimulates activity Contracts bladder Stimulates erection of sex organs Stimulates gallbladder Gallbladder Contracts pupil
  8. 8. Summary of autonomic differences Autonomic nervous system controls physiological arousal Sympathetic division (arousing) Parasympathetic division (calming) Pupils dilate EYES Pupils contract Decreases SALVATION Increases Perspires SKIN Dries Increases RESPERATION Decreases Accelerates HEART Slows Inhibits DIGESTION Activates Secrete stress hormones ADRENAL GLANDS Decrease secretion of stress hormones
  9. 9. Central Nervous System <ul><li>Brain and Spinal Cord </li></ul>Spinal Cord Brain
  10. 10. <ul><li>Left & Right sides are separate </li></ul><ul><li>Corpus Callosum : major pathway between hemispheres </li></ul><ul><li>Some functions are ‘lateralized’ </li></ul><ul><ul><li>language on left </li></ul></ul><ul><ul><li>math, music on right </li></ul></ul><ul><li>Lateralization is never 100% </li></ul>Brain has 2 Hemispheres Left Hemisphere Corpus Callosum Right Hemisphere
  11. 11. Each hemisphere is divided into 4 lobes Frontal Parietal Occipital Temporal
  12. 12. Sensory Information sent to opposite hemisphere <ul><li>Principle is Contralateral Organization </li></ul><ul><li>Sensory data crosses over in pathways leading to the cortex </li></ul><ul><li>Visual Crossover </li></ul><ul><ul><li>left visual field to right hemisphere </li></ul></ul><ul><ul><li>right field to left </li></ul></ul><ul><li>Other senses similar </li></ul>Left visual field Right visual field Optic nerves Corpus Callosum Left Visual Cortex Right Visual Cortex
  13. 13. Contralateral Motor Control <ul><li>Movements controled by motor area </li></ul><ul><li>Right hemisphere controls left side of body </li></ul><ul><li>Left hemisphere controls right side </li></ul><ul><li>Motor nerves cross sides in spinal cord </li></ul>Somatosensory Cortex Motor Cortex
  14. 14. Corpus Callosum <ul><li>Major ( but not only) pathway between sides </li></ul><ul><li>Connects comparable structures on each side </li></ul><ul><li>Permits data received on one side to be processed in both hemispheres </li></ul><ul><li>Aids motor coordination of left and right side </li></ul>Corpus Callosum Medial surface of right hemisphere
  15. 15. Corpus Callosum <ul><li>What happens when the corpus callosum is cut? </li></ul><ul><li>Sensory inputs are still crossed </li></ul><ul><li>Motor outputs are still crossed </li></ul><ul><li>Hemispheres can’t exchange data </li></ul>
  16. 16. The ‘Split Brain’ studies <ul><li>Surgery for epilepsy : cut the corpus callosum </li></ul><ul><li>Roger Sperry, 1960’s </li></ul><ul><li>Special apparatus </li></ul><ul><ul><li>picture input to just one side of brain </li></ul></ul><ul><ul><li>screen blocks objects on table from view </li></ul></ul>Nonverbal right hemisphere Verbal left hemisphere
  17. 17. <ul><li>Picture to left brain </li></ul><ul><ul><li>can name the object </li></ul></ul><ul><ul><li>left hand cannot identify by touch </li></ul></ul>The ‘Split Brain’ studies <ul><li>Picture to right brain </li></ul><ul><ul><li>can’t name the object </li></ul></ul><ul><ul><li>left hand can identify by touch </li></ul></ul>Nonverbal right hemisphere Verbal left hemisphere ?? “ What did you see?” “ Using your left hand, Pick up what you saw.” I saw an apple. “ What did you see?” Nonverbal right hemisphere Verbal left hemisphere
  18. 18. Localization of function Frontal Parietal Occipital Temporal
  19. 19. Occipital Lobe <ul><li>Input from Optic nerve </li></ul><ul><li>Contains primary visual cortex </li></ul><ul><ul><li>most is on surface inside central fissure </li></ul></ul><ul><li>Outputs to parietal and temporal lobes </li></ul>Occipital Lobe Visual Lobe
  20. 20. Temporal Lobe <ul><li>Inputs are auditory, visual patterns </li></ul><ul><ul><li>speech recognition </li></ul></ul><ul><ul><li>face recognition </li></ul></ul><ul><ul><li>word recognition </li></ul></ul><ul><ul><li>memory formation </li></ul></ul><ul><li>Outputs to limbic System, basal Ganglia, and brainstem </li></ul><ul><li>Contains primary auditory cortex </li></ul>Temporal Lobe Temporal Lobe Auditory Cortex
  21. 21. Parietal Lobe <ul><li>Inputs from multiple senses </li></ul><ul><ul><li>contains primary somatosensory cortex </li></ul></ul><ul><ul><li>borders visual & auditory cortex </li></ul></ul><ul><li>Outputs to Frontal lobe </li></ul><ul><ul><li>hand-eye coordination </li></ul></ul><ul><ul><li>eye movements </li></ul></ul><ul><ul><li>attention </li></ul></ul>Parietal Lobe Somatosensory Cortex
  22. 22. Frontal Lobe <ul><li>Contains primary motor cortex </li></ul><ul><li>No direct sensory input </li></ul><ul><li>Important planning and sequencing areas </li></ul><ul><li>Broca’s area for speech </li></ul><ul><li>Prefrontal area for working memory </li></ul>Frontal Lobe Motor Cortex Motor Cortex Broca’s Area Motor Cortex Working Memory
  23. 23. Frontal Lobe Disorders <ul><li>Broca’s area </li></ul><ul><ul><li>productive aphasia </li></ul></ul><ul><li>Prefrontal area </li></ul><ul><ul><li>lose track of ongoing context </li></ul></ul><ul><ul><li>fail to inhibit inappropriate responses </li></ul></ul><ul><li>Often measured with the Wisconsin Card Sorting Task </li></ul>
  24. 24. Wisconsin Card Sorting Task <ul><li>Patient is given a deck of 64 different cards </li></ul><ul><li>Told to place each card under the one it best matches </li></ul><ul><li>Told correct or incorrect after each card </li></ul><ul><li>Row of 4 example cards set out </li></ul><ul><li>Must deduce what the underlying rule is. </li></ul>Correct!
  25. 25. Wisconsin Card Sorting Task
  26. 26. Wisconsin Card Sorting Task
  27. 27. Wisconsin Card Sorting Task
  28. 28. Wisconsin Card Sorting Task
  29. 29. Wisconsin Card Sorting Task
  30. 30. Wisconsin Card Sorting Task
  31. 31. The Nervous System: Summary <ul><li>Major structures of the nervous </li></ul><ul><ul><li>CNS, Somatic, Autonomic </li></ul></ul><ul><ul><li>Two hemispheres & 4 lobes </li></ul></ul><ul><li>Organization </li></ul><ul><ul><li>contralateral input & output </li></ul></ul><ul><ul><li>primary sensory areas </li></ul></ul><ul><ul><li>motor areas </li></ul></ul><ul><ul><li>Commissure </li></ul></ul><ul><li>Localization of functions </li></ul>Central Nervous System Peripheral Nervous System