CORE-RS-02 The Nervous System Dr. Nelson Jiménez

The Nervous System zMajor division - Central vs. Peripheral zCentral or CNS- brain and spinal cord zPeripheral- nerves connecting CNS to muscles and organs Central Nervous System Peripheral Nervous System Author Credit: msu.edu/course/psy/101/jackson/HiAchSum2005 Revised 2010

Peripheral Nervous System z3 kinds of neurons connect CNS to the body ysensory ymotor yinterneurons zMotor - CNS to muscles and organs zSensory - sensory receptors to CNS zInterneurons: Connections Within CNS Spinal Cord Brain Nerves

Peripheral Nervous System Skeletal (Somatic) SympatheticParasympathetic Autonomic Peripheral Nervous System

Somatic System zNerves to/from spinal cord ycontrol muscle movements ysomatosensory inputs zBoth Voluntary and reflex movements zSkeletal Reflexes ysimplest is spinal reflex arc Muscle Motor Neuron Interneuron Skin receptors Sensory Neuron Brain

Autonomic System zTwo divisions: ysympathetic yParasympatheitic zControl involuntary functions yheartbeat yblood pressure yrespiration yperspiration ydigestion zCan be influenced by thought and emotion

Sympathetic z“ Fight or flight” response zRelease adrenaline and noradrenaline zIncreases heart rate and blood pressure zIncreases blood flow to skeletal muscles zInhibits digestive functions 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

Parasympathetic z“ Rest and digest ” system zCalms body to conserve and maintain energy zLowers heartbeat, breathing rate, blood pressure 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

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

Central Nervous System zBrain and Spinal Cord Spinal Cord Brain

zLeft & Right sides are separate zCorpus Callosum : major pathway between hemispheres zSome functions are ‘lateralized’ ylanguage on left ymath, music on right  Lateralization is never 100% Brain has 2 Hemispheres Left Hemisphere Corpus Callosum Right Hemisphere

Each hemisphere is divided into 4 lobes Frontal Parietal Occipital Temporal

Sensory Information sent to opposite hemisphere zPrinciple is Contralateral Organization zSensory data crosses over in pathways leading to the cortex zVisual Crossover yleft visual field to right hemisphere yright field to left zOther senses similar Left visual field Right visual field Optic nerves Corpus Callosum Left Visual Cortex Right Visual Cortex

Contralateral Motor Control zMovements controled by motor area zRight hemisphere controls left side of body zLeft hemisphere controls right side zMotor nerves cross sides in spinal cord Somatosensory CortexMotor Cortex

Corpus Callosum zMajor ( but not only) pathway between sides zConnects comparable structures on each side zPermits data received on one side to be processed in both hemispheres zAids motor coordination of left and right side Corpus Callosum Medial surface of right hemisphere

Corpus Callosum zWhat happens when the corpus callosum is cut? zSensory inputs are still crossed zMotor outputs are still crossed zHemispheres can’t exchange data

The ‘Split Brain’ studies zSurgery for epilepsy : cut the corpus callosum zRoger Sperry, 1960’s zSpecial apparatus ypicture input to just one side of brain yscreen blocks objects on table from view Nonverbal right hemisphere Verbal left hemisphere

Nonverbal right hemisphere Verbal left hemisphere ?? “What did you see?” zPicture to left brain ycan name the object yleft hand cannot identify by touch zPicture to right brain ycan’t name the object yleft hand can identify by touch “Using your left hand, Pick up what you saw.” The ‘Split Brain’ studies I saw an apple. “What did you see?” Nonverbal right hemisphere Verbal left hemisphere

Localization of function Frontal Parietal Occipital Temporal

Occipital Lobe zInput from Optic nerve zContains primary visual cortex ymost is on surface inside central fissure zOutputs to parietal and temporal lobes Occipital Lobe Visual Lobe

Temporal Lobe zInputs are auditory, visual patterns yspeech recognition yface recognition yword recognition ymemory formation zOutputs to limbic System, basal Ganglia, and brainstem z Contains primary auditory cortex Temporal Lobe Temporal Lobe Auditory Cortex

Parietal Lobe Somatosensory Cortex Parietal Lobe zInputs from multiple senses z contains primary somatosensory cortex z borders visual & auditory cortex z Outputs to Frontal lobe z hand-eye coordination z eye movements z attention

Frontal Lobe Frontal Lobe zContains primary motor cortex Motor Cortex Motor Cortex Broca’s Area Motor Cortex Working Memory zNo direct sensory input zImportant planning and sequencing areas  Broca’s area for speech zPrefrontal area for working memory

The Nervous System: Summary zMajor structures of the nervous system yCNS: Brain & Spinal Cord yPNS: Somatic, Autonomic (Sympathetic & Parasympathetic) yTwo hemispheres & 4 lobes zOrganization yAfferent (sensory) neurons- towards CNS yEfferent (motor) neurons-away from CNS ySympathetic-speeds up yParasympathetic-slows down Central Nervous System Peripheral Nervous System

The Nervous System: Summary