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February 21, 2001
John Lisman, Ph.D.
Professor, Department of Biology and
The Volen Center for ComplexSystems
Jerry Samet, Ph.D.
Associate Professor
Department of Philosophy
Chaelon Myme, Ph.D. Student
Neuroscience Program
Brandeis University
Waltham, Massachusetts
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How does the brain represent the world in our minds? What
does it mean to behave without awareness of our actions or
ourselves? How can we experience the taste of strawberries,
the moving crescendo of a symphony, the humor of a joke- all
somehow through the workings of billions of nonconscious neurons?
Long considered an indelicate topic for serious discussion
in neuroscience circles, the past decade has yielded rapprochement
between neuroscience and consciousness. Nobel laureates and
dedicated consciousness conferences have championed this cause,
coupled with a philosophy of mind resurgence and application
of neuroscientific approaches to consciousness study. Our
retreat hoped to get our complex systems community up to speed
on what these key issues and approaches are.
Central to this mission was a 90-minuto panel discussion
on consciousness with Professors Jerry Samet (Department of
Philosophy, Brandeis), John
Lisman (Department of Biology, Brandeis), and neuroscience
graduate student Chaelon Myme.
As a prelude to the panel discussion, Samet gave an overview
of the history and key features of consciousness study in
philosophy, from Descartes through a taxonomy of stances held
today. His exposition nicely laid out the scope of the discussion
so that the audience might engage the panelists in a more
informed way.
Lisman began the panel with his ideas about a stringent and
operationally defined approach to studying the mechanisms
underlying consciousness. Espousing the importance of working
memory to consciousness and the NMDA receptor to working memory,
he argued that pharmacological disruption of NMDA function
in human subjects via the NMDA blocker ketamine could yield
insights about the mechanism of consciousness. He also spoke
of unconscious processing during awake states, such as driving
a car while deeply lost in thought, and overall spoke optimistically
about the prospect of rigorous scientific study of consciousness.
Myme followed with an introduction to some of the recent
neuroscience articles about what is being called "neural correlates
of consciousness." He presented studies of binocular rivalry
(where images "compete" for visual awareness) in monkey and
in man, which suggest that the inferotemporal (IT) cortex
is activated during those moments when an object is perceived,
and not merely when it is activating the retina and initial
stages of visual brain areas. Although admitting we were a
long way off in getting to more than a coarse understanding
of consciousnss, he suggested that if IT is a key brain area
for visual awareness in humans and in monkeys, more thorough
study of the microcircuitry of IT in primates may be useful
for understanding not just neural correlates, but neural mechanisms
of consciousness.
The panelists ended with questions from the audience, sparking
a lively exchange ranging from issues of animal or artificial
consciousness to criticism of the papers presented, to a clarification
of terminology. Samet emphasized that although the "neural
correlate of consciousness" may be useful, he was pessimistic
about a satisfactory mechanistic account of conscious experience.
Some audience members also questioned whether study of consciousness
was premature at this point in our understanding of the brain.
Myme countered, ending the discussion with the sentiment of
"neurophilosopher" Patricia Churchland, that what today may
seem mysterious and inscrutable is incrementally transformed
into tomorrow's axiomatic understanding.
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