Transcript Swasson - Texas A&M University

Conceptual exploration of the
Kandel, E. R. (2000) and Swason
(2008) articles
Takashi Yamauchi
Texas A&M University
Kandel 2000
• Main messages
– Localization of mental functions
• P. 15 “Mental processes are represented in the
brain by their elementary processing operations.”
• Elementary operations of cognitive functions are
localized in the brain.
• P.15
• “We now appreciate that all cognitive abilities
result from the interaction of many simple
processing mechanisms distributed in many
different regions of the brain.”
Metaphor: railroad system
• These elementary operations are localized
but they are interconnected.
• They often work in parallel.
– “The better, more realistic metaphor is to think
of mental processes as several railroad lines
that all feed into the same terminal.” P.16
– The damage to one pathway does not
necessary interfere with the system as a
whole.
Evidence:
• Historical findings
– Ramon y Cajal
– Frantz Joseph Gall
– Pierre Paul Broca
– Karl Wernickie
– Affective traits and personality are localized.
Questions
• How much can I buy his idea of localization?
• Doesn’t this idea resonate with the “structuralist”
approach?
• If so, can’t I apply the criticism that Gestalt
psychologists raised for structuralism?
• How do you find “elementary cognitive
operations”? What criteria do we use?
Swason (2009)
• Basic characteristic
– Interconnection between structure and
function
• Evolutionary perspective
– Simple organisms that do not have a nervous
system
– Organisms with a simple nervous system
(sensory neurons, motor neurons,
interneurons)
– Vertebrate nervous systems
• First multicellular animals (akin to modernday sponges)
– No nervous system
– can’t move, but have smooth muscle cells.
– These cells (independent effectors) react
directly to environmental chemicals.
• 3min
– http://www.youtube.com/watch?v=BW05vMziy2o&feature
=fvsr
– http://www.youtube.com/watch?v=Q3AdWGElTFw
• The first animal with a nervous system.
– Jellyfish, corals, anemones, hydra
– they can move (the first accomplishment of
the nervous system appears to be
locomotion).
• 1min
• http://www.youtube.com/watch?v=GTXinF8ZVCo
Sensory neurons & Motor
neurons
• the cells facing the external environment
became specialized to detect stimuli.
– Increased stimulus sensitivity
– Faster responses
– Some localization (sensory neurons
responding to different stimulus modalities
can be distributed in different body regions.
Fig. 2.3
A: no nervous system. React directly to
environmental stimuli (e.g., sponges)
B: sensory neurons detect stimuli and send signals
directly to effector cells (e.g., muscle). They are
sensorimotor neurons.
C: sensory neurons send signals to motor neurons,
which send signals to effector cells.
interneurons
Fig. 2.5
• E.g., flatworm
http://en.wikipedia.org/wiki/Flatwo
rm
• Bilateral symmetry
• centralization
– the division of the nervous system
such as the central nervous system
and the peripheral nervous system
• cephalization
– the concentration of nervous tissues
– head
interneurons
• Create convergence and divergence of
information processing
• Excitatory and inhibitory signals.
• The vase majority of vertebrate brain
neurons are interneurons (p. 20)
vertebrates
• Animals that have backbones
• Originated 520 million years ago during the Cambrian explosion
(Wikipedia)
• The early stage of embryogenesis is basically the same in all
vertebrates.
–
–
–
–
Differentiation of the CNS and heart appear first
Prenatal brain development
2:19 min; http://www.youtube.com/watch?v=UgT5rUQ9EmQ
5:29 min http://www.youtube.com/watch?v=mMDPP-Wy3sI&feature=related
Basic plan of nervous system
connectivity
• A model of basic wiring
•There are basic
connectivity divisions in
cognitive, intrinsic, and
sensory input.
•Cognitive, intrinsic,
and sensory segments
are interconnected.
S: sensory;
I: intrinsic input;
C: cognitive input
M: motor
response
B: behavior
•Cognitive, intrinsic,
and sensory segments
receive feedback from
the motor system.
Motor systems
•Motor systems are
organized hierarchically.
•MN: motoneurons 
directly linked to muscle
fibers.
•MPG: motor pattern
generator
•MPI: motor patter initiator
(recognize and initiate
MPG)
•Cognitive, intrinsic, and
sensory segments all
intervene the three levels
directly.
Sensory systems
• There are several receptor types (e.g.,
visual, auditory, tactile, etc.)
• They work in parallel
Cognitive system
• The cerebral cortex and cerebral nuclei
(basal ganglia) are most important part of
the cognitive system
• Sensory responses  reflexive
• Cognitive responses anticipatory
• (planning, prioritizing, initiating, evaluating)
Intrinsic systems
• Sleep-wake, arousal, motivational state
• Pleasure-pain,
• Feeling / affect
How pharmacological and
genetic networks relate to
functional systems
• Pharmacological networks
– Types of neurotransmitters, their dominant
release sites
– Neurotransmitter systems are not by and
large functional systems
Summary p. 31
• “there is no simple relationship between
the CNS’s topographic or regional
differentiation and its functional
organization.”
• “The CNS is more like a network rather
than hierarchical organization.”
Overview of the adult mammalian
nervous system p. 31
• CNS and PNS