Central Nervous System

1. Describe the overall functional organization of the nervous system.
2. Discuss how the CNS is protected from both external trauma and any internal fluctuations that might occur in the body.
3. Describe the major brain regions and what each does.
4. Establish that CNS neural paths are precisely ordered for successful integration.
5. Discuss how sleep and memory are examples of CNS integration.

LECTURE OUTLINE

I.  GENERAL INTRODUCTION

  A. Introduction to the nervous system 
          1. Some functions of the nervous system
               a. Maintaining homeostasis
               b. Sensory input
               c. Motor output
               d. Emotions, memory, personality, etc.
  B. Organization of the nervous system
          1. Central Nervous System (CNS)/Peripheral Nervous System (PNS)

I. PROTECTION AND NOURISHMENT OF THE BRAIN AND SPINAL CORD

  A. CNS is well-protected from internal/external change
          1. Biochemical insults: Blood brain barrier (BBB) 
          2. Physical insults: Skull, vertebrae, and meninges
  B. Cerebrospinal Fluid (CSF)
          1. Formation by choroid plexus
          2. Composition
          3. Drainage from arachnoid villi
  C. Dysfunctions (if time permits) 

III. FUNCTIONAL ORGANIZATION OF THE BRAIN AND SPINAL CORD 

  A. Introduction
           1. Broca first showed that a specific brain structure had a function

  B. Spinal Cord
          1. Spinal cord organization/Relationship to spinal nerves
          2. Functions of the spinal cord
               a. Relays information to and from brain via ascending 
                   and decending tracts the spinal cord
               b. Pattern generators
               c. Spinal cord is involved in reflex arcs
  C. Brain: Brain stem, Cerebellum, Diencephalon, and Cerebrum 
          1. Brain stem (Midbrain, Pons, and Medulla oblongata)
               a. Site for many reflexes, some of which are homeostatic
               b. Origin of diffuse modulatory systems that project to higher brain regions
                    1) Serotonin and SSRI action
               c. Brainstem is a relay station
                    1) Convey sensory inputs to and motor outputs from the brain
                         a) Some cranial nerves are present in this brain region
           2. Cerebellum 
               a. Arbitrator of motor events
               b. Functional organization 
          3. Diencephalon (Thalamus and Hypothalamus)
               a. Thalamus is a relay station
               b. Hypothalamus is important in homeostasis, reproduction,
                   and emotional behaviors, such as stress
          4. Cerebrum 
               a. Functional organization of the cerebral cortex
                    1) Evidence from PET scans
                    2) Spatial relationships reflect functional interactions
               b. Basal nuclei (=basal ganglia)
                    1) Functions of the basal nuclei
                    2) Dysfunction: Dopamine and Parkinsonism (Animation) 
          
IV. AN EXAMPLE OF CNS INTEGRATION

   A. Emotions and Memory: Limbic system
          1. Limbic system: Role in emotions and learning
          2. Types of of memory ***
               a. Short-term (e.g. working memory) and long-term memory 
                  (e.g. procedural/reflexive or declarative memories) 
                    1) Importance of Consolidation for long-term memory 
               b. Hippocampus and new declarative memories
                    1) Why the hippocampus?  Example: HM and  amnesia
                         a) Dr. Milner's landmark conclusions after working with HM
               c. Memories are stored in various brain regions outside of
                   the hippocampus               
               d. Neuronal architecture and function of the hippocampus
                    1) Tetany of CA1 neuron results in long term potentiation (LTP) 
                    2) LTP is a long term change in the EPSP
               e. How LTP works at the level of the synapse 
                    1) Roles for Glutamate, Ca++, protein kinase, NMDA &
                       AMPA receptors, and protein synthesis in LTP
                    2) Positive feedback results in a stronger synapse 
               f. Long term depression (LTD)
                    1) Role of cerebellum in conditioning and behavior
                    2) Parallel and climbing fibers fire together to cause LTD -->

Reading assignment. Please read Chapter 10 for next lecture.