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Facility Reports and Information
University of California, Los Angeles, CA
Spatial Overlap of ON and OFF Subregions and Its Relation to Response Modulation Ratio in Macaque Primary Visual Cortex
Mario L. Mata[1] and Dario L. Ringach[2]
1 - Department of Neurobiology, David
Geffen School of Medicine; and
2 - Departments of Neurobiology and
Psychology, Biomedical Engineering Interdepartmental Program, Brain
Research Institute, Jules Stein Eye Institute, David Geffen School of
Medicine, University of California, Los Angeles, California
J Neurophysiol 93: 919-928, 2005. First published
September 15, 2004; doi:10.1152/jn.00668.2004
0022-3077/05 $8.00
Submitted 2 July 2004; accepted in final form 8
September 2004
We studied the spatial overlap of ON and OFF
subregions in macaque primary visual cortex and its relation to the
response modulation ratio (the F1/F0 ratio). Spatial maps of ON and OFF
subregions were obtained by reverse correlation with a dynamic noise
pattern of bright and dark spots. Two spatial maps, ON and OFF, were
produced by cross-correlating the spike train with the location of
bright and dark spots in the stimulus respectively. Several measures
were used to assess the degree of overlap between subregions. In a
subset of neurons, we also computed the F1/F0 ratio in response to
drifting sinusoidal gratings. Significant correlations were found among
all the overlap measures and the F1/F0 ratio. Most overlap indices
considered, and the F1/F0 measure, had bimodal distributions. In
contrast, the distance between on and off subregions normalized by their
size was unimodal. Surprisingly, a simple model that additively combines
ON and OFF subregions with spatial separations drawn from a unimodal
distribution, can readily explain the data. These analyses clarify the
relationship between subregion overlap and the F1/F0 ratio in macaque
primary visual cortex, and a simple model provides a parsimonious
explanation for the co-existence of bimodal distributions of overlap
indices and a unimodal distribution of the normalized distance.
Address for reprint requests and other correspondence:
D. Ringach, Dept of Psychology, Franz Hall, Rm 7613, University of
California, Los Angeles, CA 90095-1563 (E-mail:
dario@ucla.edu )
See:
"This lab performed animal experiments involving pain or distress but no analgesics, anesthetics or pain relievers were administered."
Return to University of California, Los Angeles, CA
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Rats, mice, birds, amphibians and other animals have
been excluded from coverage by the Animal Welfare Act. Therefore research
facility reports do not include these animals. As a result of this
situation, a blank report, or one with few animals listed, does not mean
that a facility has not performed experiments on non-reportable animals. A
blank form does mean that the facility in question has not used covered
animals (primates, dogs, cats, rabbits, guinea pigs, hamsters, pigs,
sheep, goats, etc.). Rats and mice alone are believed to comprise over 90%
of the animals used in experimentation. Therefore the majority of animals
used at research facilities are not even counted.
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