Paper Available: Model of V1 Development

[Ken Miller]

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The following paper is available by anonymous ftp.  It can also be
obtained from my web page:

http://www.keck.ucsf.edu/~ken
  (click on 'Publications';
   or alternatively, go directly to
   http://www.keck.ucsf.edu/~ken/miller.htm#references)

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E. Erwin and K.D. Miller (1998).  ``Correlation-Based Development of
Ocularly-Matched Orientation and Ocular Dominance Maps: Determination
of Required Input Activities.''  In press, Journal of Neuroscience.

ABSTRACT:
We extend previous models for separate development of ocular dominance
and orientation selectivity in cortical layer 4 by exploring
conditions permitting combined organization of both properties.  These
conditions are expressed in terms of functions describing the degree
of correlation in the firing of two inputs from the lateral geniculate
nucleus (LGN), as a function of their retinotopic separation and their
``type'' (ON-center or OFF-center, left-eye or right-eye).

The development of ocular dominance requires that an input's
correlations with other inputs from the same eye be stronger than or
equal to its correlations with inputs of the opposite eye, and
strictly stronger at small retinotopic separations.  This must be true
after summing correlations with inputs of both center types.  The
development of orientation-selective simple cells requires that (1) an
input's correlations with other inputs of the same center type be
stronger than its correlations with inputs of the opposite center type
at small retinotopic separation; and (2) this relationship reverse at
larger retinotopic separations within an arbor radius (the radius over
which LGN cells can project to a common cortical point).  This must be
true after summing correlations with inputs serving both eyes.

For orientations to become matched in the two eyes, correlated
activity within the receptive fields must be maximized by specific
between-eye alignments of ON and OFF subregions.  Thus the
correlations between the eyes must differ depending on center type,
and this difference must vary with retinotopic separation within an
arbor radius.

These principles are satisfied by a wide class of correlation
functions.  Combined development of ocularly matched orientation maps
and ocular dominance maps can be achieved either simultaneously or
sequentially.  In the latter case, the model can produce a correlation
between the locations of orientation map singularities and local
ocular dominance peaks similar to that observed physiologically.

The model's main prediction is that the above correlations should
exist among inputs to cortical layer 4 simple cells before vision.  In
addition, mature simple cells are predicted to have certain
relationships between the locations of the ON and OFF subregions of
the left- and right-eyes' receptive fields.

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Ken Miller
 
        Kenneth D. Miller               telephone: (415) 476-8217
        Dept. of Physiology		fax: (415) 476-4929
        UCSF                            internet: ken at phy.ucsf.edu
        513 Parnassus			www: http://www.keck.ucsf.edu/~ken
        San Francisco, CA 94143-0444