June 2006
Volume 6, Issue 6
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Vision Sciences Society Annual Meeting Abstract  |   June 2006
The initial ocular following responses (OFRs) to competing visual motions: Contrast-dependent nonlinear interactions and their dependence on spatial frequency and speed
Author Affiliations
  • Boris M. Sheliga
    Lab Sensorimotor Research, Natl Eye Inst/NIH, Bethesda, MD, USA
  • Edmond J. FitzGibbon
    Lab Sensorimotor Research, Natl Eye Inst/NIH, Bethesda, MD, USA
  • Frederick A. Miles
    Lab Sensorimotor Research, Natl Eye Inst/NIH, Bethesda, MD, USA
Journal of Vision June 2006, Vol.6, 80. doi:10.1167/6.6.80
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      Boris M. Sheliga, Edmond J. FitzGibbon, Frederick A. Miles; The initial ocular following responses (OFRs) to competing visual motions: Contrast-dependent nonlinear interactions and their dependence on spatial frequency and speed. Journal of Vision 2006;6(6):80. doi: 10.1167/6.6.80.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

We used the electromagnetic search coil technique to record the initial (open-loop) OFRs elicited in human Ss by horizontal apparent motion applied to vertical grating patterns composed of two sinusoids. The two sinusoids always shifted in opposite directions and their contrasts were varied independently over the range 0–64%. We previously reported (VSS 2005) that when the contrast of one sinusoid was less than about half that of the other, the sinusoid with the higher contrast dominated initial OFRs and the sinusoid with the lower contrast had almost no influence: winner-take-all. When their contrasts were more similar, both sinusoids exerted an influence on initial OFRs: vector sum/averaging. We attributed this nonlinear dependence on the relative contrasts of the two sinusoids to mutual inhibition between the neural elements processing the two motions. In those experiments the two sinusoids differed in both spatial frequency and speed (ratio, 3:5), and in the present experiments the two sinusoids had either (a) the same spatial frequency and different apparent speeds (ratio, 2:1) or (b) the same apparent speed and different spatial frequencies (ratio, 2:1). The nonlinear dependence on the relative contrasts of the two sinusoids was still apparent but less dramatic, so that dominance by one or other sinusoid now required a larger difference in their contrasts: average increase, 174% (range, 145–259%). These results suggest that the postulated mutual inhibition is stronger between neural elements that differ in their tuning for spatial frequency or speed.

Sheliga, B. M. FitzGibbon, E. J. Miles, F. A. (2006). The initial ocular following responses (OFRs) to competing visual motions: Contrast-dependent nonlinear interactions and their dependence on spatial frequency and speed [Abstract]. Journal of Vision, 6(6):80, 80a, http://journalofvision.org/6/6/80/, doi:10.1167/6.6.80. [CrossRef]
Footnotes
 Support Contributed By: NEI Intramural Program
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