Pupillometric investigation of an S-cone generated response in humans

The development of an objective method for recording S-cone signals has not progressed as far in the field of pupillometry as in electroretinography (e.g., Sawusch, Pokomy & Smith, 1987) or visually-evoked cortical potentials (e.g., Gouras et al., 1993). While previous pupil studies provided converging evidence that S-cone signals contribute to the pupillary response (Banks & Munsinger, 1974; Young & Alpern, 1980; Krastel et al., 1985; Verdon & Howarth, 1988; Kimura & Young, 1994a), it is presently unclear whether or how well an S-cone generated pupillary response can be recorded without contamination from M- and L- cone generated responses. The ideal method would produce isolation of substantially large S-cone generated responses over a wide wavelength and intensity range.