Elsevier

Vision Research

Volume 43, Issue 25, November 2003, Pages 2707-2719
Vision Research

Contrast coding and magno/parvo segregation revealed in reaction time studies

https://doi.org/10.1016/S0042-6989(03)00408-5Get rights and content
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Abstract

Reaction times (RTs) are obtained for a wide range of contrasts of vertical sinusoidal gratings. The data are plotted as a function of the reciprocal of contrast. In some conditions, a single linear function accounts for the data. In others a clear bi-linear function is obtained. The low and high contrast regions of the function are interpreted as representing magno and parvo activity, respectively. RT-based supra-threshold sensitivity functions are obtained for different luminances, stimulus durations and eccentricities and these are compared with conventional threshold-based sensitivities to establish the extent to which RTs and contrast sensitivity are constrained by the same sensory processes.

Keywords

Parvo-cellular
Magno-cellular
Reaction times
Sinusoidal gratings
Contrast spatial frequency

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