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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: [email protected]  


"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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