Organization of the nervous system 3
Raghav Rajan
Bio 334 – Neurobiology I
August 26th 2013
26th August 2013
Bio 334 - Neurobiology I - Organization of the nervous system 3
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Spinal cord
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Dorsal roots carry
sensory information
Ventral roots carry
motor information
Controls voluntary
and reflexive
movements
Receives sensory
input from skin,
joints, muscles
Paralysis inferior to
location of damage
Bio 334 - Neurobiology I - Organization of the nervous system 3
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Mark F Bear, Barry W Connors, Michael A Paradiso. Neuroscience: Exploring the brain (2007) – Chapter 7
PNS
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Somatic PNS – related to
voluntary control
Visceral PNS – involuntary –
innervates internal organs,
glands, blood vessels, etc.
Bio 334 - Neurobiology I - Organization of the nervous system 3
http://en.wikipedia.org/wiki/Peripheral_nervous_system
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General functions of nervous system
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To find food
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To avoid being eaten
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To reproduce
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Bio 334 - Neurobiology I - Organization of the nervous system 3
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Evolution of complex nervous systems
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Evolution selects for adaptations that promote the ability
to pass on genetic material
Works on what is already there
Needs some amount of redundancy to tinker and make
changes
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Bio 334 - Neurobiology I - Organization of the nervous system 3
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General principles of organization of nervous system
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Organization of sensory and motor areas dependent on
environment, relative importance of different sense
organs, motor capabilities
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Based on anatomy, we can delineate functional systems
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Functional systems are organized into maps
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Hierarchy of functional systems?
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Functional systems on one side of the brain (cerebral
cortex) get information and control the contralateral side
of the body
Kandel, Schwartz and Jessell, Principles of Neural Science
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Bio 334 - Neurobiology I - Organization of the nervous system 3
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Sensory and motor cortical representations not
proportional to external size
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http://www.autismindex.com/Therapies/Therapy_Key_Word_Site_Map/sensory/motor_sensory_homunculus.html
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Important sensory organs are better represented in
the cortex and sub-cortical structures
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http://www.pnas.org/content/109/Supplement_1/10647.long
Bio 334 - Neurobiology I - Organization of the nervous system 3
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Functional systems – like the visual system – two
streams of processing
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Dorsal pathway - “vision
for action” - where
Ventral pathway - “vision
for perception” - what
Now, considerable
evidence for interaction
between both pathways
http://www.waece.org/cd_morelia2006/ponencias/stoodley.htm
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Bio 334 - Neurobiology I - Organization of the nervous system 3
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Maps – sensory, motor, etc.
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http://uc.exteenblog.com/highwind/images/Know/brain_homunculus1.jpghttp://w
ww.wiringthebrain.com/2010_12_01_archive.html
Bio 334 - Neurobiology I - Organization of the nervous system 3
http://neurowww.cwru.edu/faculty/strowbridge/OlfactoryBulb/bulb1.htm
http://www3.unil.ch/wpmu/neuroaudio/resaerch/auditory-cortex/
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Hierarchichal processing within functional systems – is
there really a hierarchy?
Felleman DJ, Van Essen DC. Distributed hierarchical processing in the primate
cerebral cortex. Cerebral Cortex (1991)
http://www.cse.buffalo.edu/~rapaport/575/F07/006010.jpg
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Bio 334 - Neurobiology I - Organization of the nervous system 3
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Plasticity – changes in strength of connections not
reflected in simple anatomy
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In congenitally blind
people, primary
visual cortex is
active during
sentence
comprehension task
http://www.pnas.org/content/108/11/4429.long
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Bio 334 - Neurobiology I - Organization of the nervous system 3
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Assignment on disorders
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1 page write-up – in layman language
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Description of disorder
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Present understanding of the cause?
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What does this tell us about the brain?
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Caveats
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Send by email before the 2nd of September
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