Nervous System – Part 2 Review PNS Divisions Brain Afferent Division Efferent Division Somatic Autonomic Sympathetic Parasympathetic Brain Lateralization Localization of Function Brain Regions

Nervous System Review 2 major divisions: Central Nervous System Peripheral Nervous System 2 major divisions: Central (CNS)- brain and spinal cord Peripheral (PNS)- nerves connecting CNS to sences, muscles, and organs

Nervous System Review 3 kinds of neurons: Nerve = many neurons Afferent (Sensory) Neurons How a signal is received Interneurons Integrates Completely within the CNS Efferent (Motor) Neurons Outgoing info to muscles and organs Nerve = many neurons key words: peripheral nervous system

Peripheral Nervous System Consists of 43 paired nerves. Contain axons of both afferent and efferent neurons.

Peripheral Nervous System Afferent Division Efferent Division Somatic A u t o n o m i c key words: peripheral nervous system; skeletal nervous system; somatic nervous system; autonomic nervous system; sympathetic nervous system; parasympathetic nervous system 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

PNS – Afferent Division Takes in sensory input. Ex)

PNS – Efferent Division Carry signals out from the CNS to muscles and glands. More complicated. Made up of somatic and autonomic divisions.

PNS – Efferent Division – Autonomic Division Controls signals to/from internal organs Control involuntary functions heartbeat blood pressure respiration perspiration digestion Can be influenced by thought and emotion Two divisions: sympathetic parasympathetic

PNS – Efferent Division – Autonomic - Sympathetic 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 “Fight-or-flight” response Release adrenaline and norepinephrine Increases heart rate and blood pressure Increases blood flow to skeletal muscles Inhibits digestive functions keywords: sympathetic nervous system; fighlt or flight response

PNS – Efferent Division – Autonomic - Parasympathetic 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 “Rest-and-digest ” system Calms body to conserve and maintain energy Lowers heartbeat, breathing rate, blood pressure key words: parasympathetic nervous system; rest and digest system

Reflexes

Nervous System High in lipids White matter consists mostly of myelinated axons. High in lipids Based on color when preserved in formaldehyde http://www.youtube.com/watch?v=DJe3_3XsBOg Gray matter is non-myelinated axons and cell bodies. White matter can look darker than gray depending on the type of stain used.

Brain has 2 Hemispheres Left & Right sides are separated Corpus Callosum: major pathway between hemispheres Some functions are ‘lateralized’ language on left math, music on right Lateralization is never 100% Left Hemisphere Corpus Callosum Right key words: left hemisphere; right hemisphere

Sensory Information sent to opposite hemisphere Left visual field Right visual Optic nerves Corpus Callosum Left Visual Cortex Right Visual Sensory data crosses over in pathways leading to the cortex Visual Crossover left visual field to right hemisphere right field to left Other senses and motor control is similar key words: left hemisphere; right hemisphere; visual infomation; touch information

Corpus Callosum Major (but not only) pathway between sides Connects comparable structures on each side Permits data received on one side to be processed in both hemispheres Aids motor coordination of left and right side Corpus Callosum Medial surface of right hemisphere Example : You read a geometry problem in a textbook. The words are seen and the visual forms translated into meaning by the language center in the left hemisphere. To solve the problem you have to imagine a cone shaped object. This is accomplished by centers in the right hemisphere. The solution is written down using language generated by the left hemisphere. What would happen in cases like this if the callosum was damaged ?

Corpus Callosum What happens when the corpus callosum is cut? Sensory inputs are still crossed Motor outputs are still crossed Hemispheres can’t exchange data key words: left hemisphere; right hemisphere; corpus callosum; epilepsy One method used to treat severely epileptic patients involves cutting the corpus callosum to prevent the spread of seizures acorss the entire brain. The video clip on this slide shows a man who has had such a surgery. Double click on video to start video clip. This clip discusses the types of information processing deficits associated with cutting the corpus callosum and shows a task often used to assess corpus callosum damage. This task is also represented in drawing form on the following slide as well.

The ‘Split Brain’ studies Surgery for epilepsy: cut the corpus callosum Special apparatus picture input to just one side of brain screen blocks objects on table from view Nonverbal right hemisphere Verbal left key words: left hemisphere; right hemisphere; corpus callosum; epilepsy This slide is a schematic of the task shown in the video clip on the previous slide

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

Localization of function Frontal Parietal Occipital Temporal key words: cerebral cortex; lobes; frontal; parietal; temporal; occipital

Occipital Lobe Input from Optic nerve Contains primary visual cortex most is on surface inside central fissure Outputs to parietal and temporal lobes Occipital Lobe Visual Lobe

Temporal Lobe Inputs are auditory, visual patterns Contains primary auditory cortex Temporal Lobe Auditory Cortex Inputs are auditory, visual patterns speech recognition face recognition word recognition memory formation Outputs to limbic system, basal ganglia, and brainstem Temporal Lobe

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

Frontal Lobe Contains primary motor cortex No direct sensory input Working Memory Motor Cortex Broca’s Area Contains primary motor cortex No direct sensory input Important planning and sequencing areas Broca’s area for speech key words: cerebral cortex; lobes; frontal; motor functions Frontal lobe is not directly involved in sensation or perception. Its functions are related to motor action (behavior). The motor cortex is the start of nerves that run through the spinal cord to the muscles. Broca’s area organizes sequences of speech movements. Damage leads to productive aphasia Dorsolateral Prefrontal Cortex is important in working memory. WM is short term memory for information needed to maintain a context, to prepare for the next step in a sequence of thought, and /or to inhibit irrelevant responses The wisconsin card sorting task illustrates the importance of working memory in maintaining context and inhibiting irrelevant responses Prefrontal area for working memory

Regions of the Brain Forebrain Midbrain Hindbrain Cerebrum Thalamus Hypothalamus Pituitary Gland Pineal Gland Midbrain Tectum Hindbrain Pons Cerebellum Medulla Oblongata

Forebrain Functions Cerebrum – coordinates sensory and motor input; memory; abstract thought Thalamus – relay station for info in/out of cerebrum Hypothalamus – maintains homeostasis Pituitary Gland – master endocrine gland; controlled by the hypothalamus Pineal Gland – controls daily rhythms

Midbrain & Hindbrain Functions Tectum – auditory and visual reflexes Pons – bridge between the cerebrum and cerebellum and medulla Cerebellum – unconscious motor coordination Medulla Oblongata – autonomic function of vital organs

http://www.pbs.org/wgbh/nova/body/how-memory-works.html (10min) Memory http://www.pbs.org/wgbh/nova/body/how-memory-works.html (10min)