@InProceedings{schwartz1994:cortical,
author = {Schwartz, E. L. and Rojer, A. S.},
title = {Cortical hypercolumns and the topology of random
orientation maps},
editor = {Shmuel Peleg and Shimon Ullman},
booktitle = {Proceedings of the 12th IAPR International
Conference on Pattern Recognition},
pages = {150--155},
year = 1994,
volume = 2,
month = {9-13 Oct.},
datestr = 199410,
organization = {Int. Association for Pattern Recognition, IEEE
Comput. Soc., Inf. Process. Assoc. Israel},
publisher = {IEEE Comput. Soc. Press},
http =
{http://ieeexplore.ieee.org/servlet/opac?punumber=4428},
url =
{http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arNumber=576893},
ISBN = 0818662654,
OCLC = 4992246,
abstract = {Smoothing a random pattern of orientations causes
the appearance of orientation ``vortices.'' These
patterns are similar to the hypercolumn pattern of
orientation tuning in monkey visual cortex, and to
the ``pinwheels'' that have been observed in cat
area 18. The generic presence of such patterns in
continuous orientation maps is a consequence of a
basic topological theorem (nonretraction of
$R^2\rightarrow S^1$), together with the stochastic
properties of random orientation
distributions. There as a close correspondence
between experimental results from cat area 18 and
computer simulations based on smoothed random
orientations. Several of the qualitative features of
cortical hypercolumn patterns, including the
``puff-extra'' structure of monkey V-1, are evident
in our simulations. There are two important
conclusions from this work. (1) Experimental
observation of orientation ``vortex'' structure in
any visually excitable neural tissue must be
evaluated in the light of the null hypothesis that
these patterns are readily formed from smoothed,
random orientation distributions, (2) The underlying
explanation for the ``vortex'' patterns which likely
exist in primate and cat visual cortex is
fundamentally topological, and follows directly from
the definition of orientation, and the existence of
local correlation of orientation in cortex.},
keywords = {topology; random orientation maps; smoothing;
orientation vortices; orientation tuning; monkey
visual cortex; pinwheels; continuous orientation
maps; random orientation distributions; cortical
hypercolumn patterns; puff-extra structure; monkey
V-1; visually excitable neural tissue; null
hypothesis; cat visual cortex area 18; primate
visual cortex},
}