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Facility Reports and Information
University of California, Los Angeles, CA
Correlation of local and global orientation and spatial frequency tuning in macaque V1
Dajun Xing[1], Dario L. Ringach[2], Robert
Shapley[1] and Michael J Hawken[1]
1 - Center for Neural Science, New York
University, New York, NY 10003, USA
2 - Departments of Neurobiology,
Psychology, and, Brain Research Institute, University of California, Los
Angeles, Los Angeles, CA 90095, USA
J Physiol 557.3 pp 923-933
DOI: 10.1113/jphysiol.2004.062026
© The Physiological Society 2004
Visual cortical neurones display a variety of visual
properties. Among those that emerge in the primary visual cortex V1 are
sharpening of selectivity for spatial frequency and for orientation. The
selectivity for these stimulus attributes can be measured around the
peak of the tuning function, usually as bandwidth. Other selectivity
measures take into account the response across a broader range of
stimulus values. An example of such a global measure is the circular
variance of orientation tuning. Here we introduce a similar measure in
the spatial frequency domain that takes into account the shape of the
tuning curve at frequencies lower than the peak, called the low-spatial
frequency variance. Our recent studies with dynamic stimuli suggest that
the selectivity for spatial frequency and orientation is strongly
correlated with the degree of suppression at low spatial frequencies and
off-axis orientations. Here we extend the study of the global tuning to
stimulus conditions that measure the response of cells to the
presentation of drifting sinusoidal grating stimuli for periods of a few
seconds. We find that under such steady-state stimulus conditions there
is a strong correlation between the global selectivity measures,
orientation circular variance and low spatial frequency variance.
Consistent with previous studies, there is a weaker correlation between
the local tuning measures, orientation and spatial frequency bandwidth.
These results support the idea that there are multiple factors that
contribute to tuning and that suppression observed in dynamic
experiments is also likely to contribute to the global selectivity for
steady-state stimuli.
(Received 30 January 2004; accepted after revision 16
April 2004; first published online 16 April 2004)
Corresponding author D. Xing: Center for Neural
Science, New York University, New York, NY 10003, USA. Email:
xdj@cns.nyu.edu
See:
"This lab performed animal experiments involving pain or distress but no analgesics, anesthetics or pain relievers were administered."
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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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