Abstract

Short wavelength-sensitive (SWS) cones have been demonstrated to contribute to visual tasks requiring spatial information (e.g., stereo). These findings necessarily imply that spatial frequency mechanisms (SFMs) exist, which receive SWS cone signals. We determined the number and frequency tuning of SFMs, receiving SWS cone signals, by isolating SWS cones with intense yellow adaptation and measuring threshold elevation functions for blue, spatially localized test stimuli (i.e., DOGs or D6s) masked by obliquely oriented, blue cosine gratings. The intensity of the yellow adapting field required for SWS cone isolation was determined by identifying the adapting intensity beyond which acuity for blue gratings became independent of further increases in field intensity. Spatial frequency of the cosine gratings and peak spatial frequency of the test stimuli varied from 0.25 to 2.83 cpd in 0.5 octave steps. The resulting threshold elevation functions, derived in this manner, define at least two clusters peaking at ~0.7 and 1.4 cpd.

© 1989 Optical Society of America