Review Part 3'

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Review Part 3.

• Bio 3411
• Monday
• December 12, 2005

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Lecture II. The Nervous System and Its Cells

• Topic
• A Few Facts
• Main Features of Nervous System
• Cells of Nervous System
• Importance in Health and in Disease
• Emphasis
• Expensive to operate
• Regions and structure reflect phylogeny
• Soma, dendrites, axon and synapses
• Burden of brain diseases - social and economic

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THE BRAIN ATLAS 2nd ed, p. 8
Mid-line (sagittal) section through central
nervous system (CNS). Note the relationship
between vertebrae (BLACK), segments of the spinal
cord (RED) and spinal nerves (YELLOW).
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THE BRAIN ATLAS 2nd ed, p. 9
The different regions of the brain from the
lateral (side) and median section (middle) human
brain. These brain regions are discernable in in
all vertebrates and in early embryos. (cerebral
cortex gold thalamus blue/purple midbrain
orange pons purple, cerebellum blue medulla
red/orange spinal cord green)
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Photograph of neurons stained by Golgis method
which fills processes of some cells with black
precipitates of heavy metals and Nissl which
stains all nuclei and neuronal cytoplasm blue.
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A neuron grown in tissue culture that is stained
with antibodies for pre and post synaptic
proteins. Red shows presynaptic and green shows
postsynaptic localization. Yellow indicates close
proximity of the two at synapses. This picture
indicates the number, distribution and density of
synapses on a nerve cell the role of which is to
integrate information from many sources.
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Lecture XVI. Genetics and Human Brains Clues
from Abnormalities.

• Topic
• Genetics and Humans
• MRDD (mental retardation and developmental
  disabilities)
• Humans
• Mice
• Whats with the Brain?
• Emphasis
• Human diseases can inform about genes and
  function
• Several disorders of development identify brain
  genes
• These genes are placed in animals to evaluate
  function
• Is the bigger human brain more or less complex?

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Victor McKusick organized a catalog of human
inherited conditions first published in 1966.
Since then the number has grown approximately 15
fold. Of these, an increasing number of
conditions has been identified as having some
component related to the nervous
system. From McKusick 2001 JAMA
Added After Lecture 10/28/05
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From Bellugi et al 2001 TINS
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From Bellugi et al 2001 TINS
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Lecture XXII. The Spinal Cord, Reflexes and
Brain Pathways.

• Topic
• Spinal Cord - Columns Horns Spinal Segments
• Spinal Nerves- Dermatomes Motor Units
• Reflexes - Knee Jerk- Myotatic or Stretch
  Reflex Withdrawal Crossed Extensor Reflexes
• Two Spinal Pathways - Sensory - Dorsal Column/
  Medial lemniscus Motor - Cortico-spinal Tract
• Emphasis
• Segmental and longitudinal organization of Cord
• Primal organization of sensory and motor systems
• A central sensory pathway (DC/ML)
• A central motor pathway (CST)

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Segmental nerve (dorsal root sensory - touch
ventral root motor -movement dorsal root
ganglion sensory nerve cell bodies)
Periphery (skin, muscle, etc.)
Spinal cord
back dorsal
front ventral
Mixed spinal nerve
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THE BRAIN ATLAS 2nd ed, p. 185
Face
Hand
Body
Foot
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THE BRAIN ATLAS 2nd ed, p. 201
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Pathways - Primitive gt Evolved (Synapse
Synapse Number)
Intraspinal Pathways
Ascending Sensory Pathway
Descending Motor Pathway
Midline
Midline
Midline
Midline
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1
2
1
1
1
Knee Jerk 1
Antagonist Inhibition 2
Dosal Column/ Medial Lemniscus Pathway 2
Corticospinal Pathway 1
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Lecture XXIII. Brain Pathways Sensation
Movement.

• Topic
• Sensation - Sensory Transduction Receptive
  Fields Adaptation Feature Detection Maps
• Movement - CST Activation, Map Force
  Direction Motor Pathways to Spinal Cord
  Descending Control of Movement CST Effects of
  Lesions
• Emphasis
• Similarities between receptive field (sensory)
  and movement commands (motor)
• Multiple pathways for touch and movement -
  function/phylogeny
• Sensory and motor maps (cortex and everywhere
  else)

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General Scheme for Neuron Adaptation
Sensory Neuron
Rapidly Adapting
Rapidly/ Slowly Adapting
Slowly Adapting
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Each small vertical line marks an action
potential of the neuron.
A neuron in the motor cortex of of an awake
behaving monkey fires in relation to the
direction of the movement (see tuning curve -
left).
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The left hemisphere of the monkey brain - Motor
(Ms) and Somatosensory (Sm) Maps
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Lecture XXIV. Higher Functions.

• Topics
• Methods for study of human brain
  function/structure
• Auditory pathways
• Language
• Hemispheric specialization
• Special talents and genius
• Emphasis
• Study by lesions (behavior), comparison,
  recording, EEG and imaging (CAT, PET, MRI)
• Differences in audition and speech related to
  structure and experience
• Structure correlates with ability

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Dr. Marcus Raichle and his colleagues at
Washington University pioneered the use of
positron emission tomography (PET also developed
here) to study complex behaviors such as
language. Here he injects tracers into a
volunteer. The volunteers head is in an early
device to monitor regional changes in
radioactivity.
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Touch
Movement
Angular gyrus
Brocas area
Vision
Hearing
Wernickes area
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Albert Einstein for my scientific thinking
words do not seem to play any role but there
is associative play of more or less clear
images of a visual and muscular type.
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Lecture XXV. Experience and Critical Periods (aka
Plasticity).

• Topics
• Morphological plasticity
• Functional plasticity
• Adult plasticity
• Mechanism(s)
• Emphasis
• Different manifestations vary with age, target
  and degree
• Permits adaptation to unspecified inputs,
  assessment of experience and adjustment to
  changes in the organism and environment over time
  
• Mechanisms include changes in connections,
  functions of regions, synaptic strength and decay
  of same

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Martin et al (1996) Brain 1191183 1191199.
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Cerebellar Cortex - Circuits
Parallel Fibers (Execution in)
Purkinje Cell (Out)
Granule Cell (Execution in)
Climbing Fiber (Intent in)
Mossy Fiber (Execution in)
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Lecture XXVI. Brain Diseases I.

• Topics
• Motor Systems - Reprise
• Pyramidal and Extrapyramidal (Basal ganglia)
• Parkinsonism a Movement Disorder
• Mechanisms and Treatment Strategies
• Empahsis
• Add ons - Cerebellum/basal ganglia modulate
  production and outcomes
• Mechanisms emphasize inhibition (economy)
• Parkinsonism is a consequnce of degeneration of
  particular neurons
• Treatments include drugs (replace transmitters),
  lesions (modulate activity irreversibly) or
  devices (control modulation of activity)

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Neuroscience, Fig 15.1, p. 372
Descending systems from the brain influence cells
in the spinal cord to create movements. The
cerebellum and the basal ganglia indirectly
influence movements as indicated schematically
here.
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THE BRAIN ATLAS, 2nd ed, p. 211
Sections
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excitatory
excitatory
excitatory
inhibitory
inhibitory
inhibitory
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Lecture XXVII. Brain Diseases II.

• Topics
• Widespread Systems
• Mood Disorders
• Depression
• Manic/Depressive Illness
• Schizophrenia
• Drugs
• Emphasis
• Monaminergic (DA, NE, 5-HT, etc) systems modulate
  broadly
• Mental illness is prevalent, persistent and has
  strong genetic components
• Treatments (and elucidation) based in part on
  natural history
• Recreational drugs activate CNS pleasure centers

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Sites of self stimulation in the rat (arrows)
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The Rosetta Stone (left) permitted the
translation of older Egyptian texts into Greek.
Words in the former is based on a large number of
unique picture based symbols each with a
different meaning the latter on different
arrangements of a small number of symbols
(letters) which have no meaning unless arranged
as words abbreviations, etc. (See add below.)
Rx After Lecture 10/28/05
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