Friday 1 December 2000
Breckenridge, Colorado
Abstract
Understanding computation in the cortical column is a holy grail for both
experimental and theoretical neuroscience. The basic six-layered
neocortical columnar microcircuit, implemented most extensively (and perhaps
in its most sophisticated form) in the human brain, supports a huge variety
of sensory, cognitive, and motor functions. The secret behind the
incredible flexibility and power of cortical columns has remained elusive,
but new insights are emerging from several different areas of research.
It is a great time for cortical anatomists, physiologists, modellers, and
theoreticians to join forces in attempting to decipher computation in the
cortical column.
In this workshop, leading experimental and theoretical neuroscientists
presented their own visions of computation in the cortical column, and
debated their views with an interdisciplinary audience. During the
morning session, speakers and panel members analyzed columnar computation
from their perspectives as authorities on the anatomy, physiology, comparative
structure, and network properties of cortical microcircuitry. Speakers
and panelists in the afternoon session considered the functional significance
of the cortical column in light of their expert knowledge of two columnar
systems which have attracted intensive experimental attention to date:
the visual cortex of cats and primates, and the barrel cortex of rodents.
The goal of the workshop was to define answers to the following questions,
examining computation in the cortical column from multiple perspectives.
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An anatomical perspective: Does a common denominator, a repeating
microcircuit element, exist across the neocortex? What evidence is
there for and against the existence of such an anatomical entity?
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A cellular and synaptic perspective: How do the cell types
differ in the form of their inputs, the patterning of their outputs, and
the transformations they perform? How does the diversity of cell
types and synapses in cortex contribute to computation within a column?
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A network perspective: Six layers, extensively recurrently
interconnected. What are the computational advantages of this layered
neocortical structure? To what extent do the layers interact, and
is this interaction crucial to the operation of the column? Does
the column work as a unit or can layers operate independently? What
is the computational advantage of the immense recurrent circuitry?
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A comparative perspective: Are there common themes for columnar
function in cortex? How do different cortical areas (e.g., visual,
auditory, and somatosensory cortex) in different species compare in terms
of columnar organization and distribution of response properties across
cortical layers?
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A physiological perspective - visual cortex: What information
reaches a column in primary visual cortex from the thalamus, and what information
is sent to the column from other areas? How is this information integrated
and transformed within the column?
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A theoretical perspective - visual cortex: What components
of the cortical column, and what rules of columnar organization, are sufficient
to generate visual feature selectivity?
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A physiological perspective - barrel cortex: How do the different
layers and columns in barrel cortex interact during tactile perception,
and how are those interactions affected by learning?
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A theoretical perspective - barrel cortex: What does the example
of barrel cortex reveal about how cortical networks extract information
from their inputs? What is a cortical network, how many neurons make
a network, and how independent are different networks?
Last revised: 01/26/01