Abstract
Purpose: We sought to measure the chromatic impulse response function (IRF) of an isolated human S-cone pathway. Previously measured chromatic IRFs were obtained using short-wave stimuli to which not only S-cones, but M- and/or L-cones may have been sensitive. Method: 10 normal trichromats served as subjects. Their IRFs were measured with a double-pulse method in which the pulses were chromatically modulated at constant luminance (based on 18 Hz heterochromatic flicker photometry). Chromatic stimuli were presented as a Gaussian patch (1 SD = 2.3 deg) in one of four quadrants around a central fixation cross on a CRT screen. Each of the two pulses (6.67 ms) was separated by an interstimulus interval from 20 to 360 ms. Chromaticity of the pulses was changed from the equal-energy white of the background to a bluish color along individually determined tritan lines (based on color matching under strong S-cone adaptation from a 420 nm background superimposed in Maxwellian view). Chromatic detection thresholds were determined by a four-alternative forced-choice method with staircases for each SOA in one session. Measurements were repeated in at least four sessions for each observer. Results and Discussion: IRFs were calculated by varying four parameters of an exponentially-damped sinewave (Burr and Morrone, JOSA A 10, 1993). S-cone IRFs have only an excitatory phase and a much longer time course compared with luminous IRFs measured by the same apparatus and on the same observers. The duration of S-cone IRFs is ∼200 ms whereas the duration of the excitatory phase of luminous IRFs is ∼40-60 ms. Individual differences in the S-cone IRF are much greater than for luminous IRFs.
| Original language | English (US) |
|---|---|
| Journal | Journal of Vision |
| Volume | 2 |
| Issue number | 10 |
| DOIs | |
| State | Published - 2002 |
Fingerprint
Keywords
- Color & optics posters
ASJC Scopus subject areas
- Ophthalmology
Cite this
The impulse response of an S-cone pathway. / Shinomori, Keizo; Werner, John S.
In: Journal of Vision, Vol. 2, No. 10, 2002.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The impulse response of an S-cone pathway
AU - Shinomori, Keizo
AU - Werner, John S
PY - 2002
Y1 - 2002
N2 - Purpose: We sought to measure the chromatic impulse response function (IRF) of an isolated human S-cone pathway. Previously measured chromatic IRFs were obtained using short-wave stimuli to which not only S-cones, but M- and/or L-cones may have been sensitive. Method: 10 normal trichromats served as subjects. Their IRFs were measured with a double-pulse method in which the pulses were chromatically modulated at constant luminance (based on 18 Hz heterochromatic flicker photometry). Chromatic stimuli were presented as a Gaussian patch (1 SD = 2.3 deg) in one of four quadrants around a central fixation cross on a CRT screen. Each of the two pulses (6.67 ms) was separated by an interstimulus interval from 20 to 360 ms. Chromaticity of the pulses was changed from the equal-energy white of the background to a bluish color along individually determined tritan lines (based on color matching under strong S-cone adaptation from a 420 nm background superimposed in Maxwellian view). Chromatic detection thresholds were determined by a four-alternative forced-choice method with staircases for each SOA in one session. Measurements were repeated in at least four sessions for each observer. Results and Discussion: IRFs were calculated by varying four parameters of an exponentially-damped sinewave (Burr and Morrone, JOSA A 10, 1993). S-cone IRFs have only an excitatory phase and a much longer time course compared with luminous IRFs measured by the same apparatus and on the same observers. The duration of S-cone IRFs is ∼200 ms whereas the duration of the excitatory phase of luminous IRFs is ∼40-60 ms. Individual differences in the S-cone IRF are much greater than for luminous IRFs.
AB - Purpose: We sought to measure the chromatic impulse response function (IRF) of an isolated human S-cone pathway. Previously measured chromatic IRFs were obtained using short-wave stimuli to which not only S-cones, but M- and/or L-cones may have been sensitive. Method: 10 normal trichromats served as subjects. Their IRFs were measured with a double-pulse method in which the pulses were chromatically modulated at constant luminance (based on 18 Hz heterochromatic flicker photometry). Chromatic stimuli were presented as a Gaussian patch (1 SD = 2.3 deg) in one of four quadrants around a central fixation cross on a CRT screen. Each of the two pulses (6.67 ms) was separated by an interstimulus interval from 20 to 360 ms. Chromaticity of the pulses was changed from the equal-energy white of the background to a bluish color along individually determined tritan lines (based on color matching under strong S-cone adaptation from a 420 nm background superimposed in Maxwellian view). Chromatic detection thresholds were determined by a four-alternative forced-choice method with staircases for each SOA in one session. Measurements were repeated in at least four sessions for each observer. Results and Discussion: IRFs were calculated by varying four parameters of an exponentially-damped sinewave (Burr and Morrone, JOSA A 10, 1993). S-cone IRFs have only an excitatory phase and a much longer time course compared with luminous IRFs measured by the same apparatus and on the same observers. The duration of S-cone IRFs is ∼200 ms whereas the duration of the excitatory phase of luminous IRFs is ∼40-60 ms. Individual differences in the S-cone IRF are much greater than for luminous IRFs.
KW - Color & optics posters
UR - http://www.scopus.com/inward/record.url?scp=4143084971&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=4143084971&partnerID=8YFLogxK
U2 - 10.1167/2.10.40
DO - 10.1167/2.10.40
M3 - Article
AN - SCOPUS:4143084971
VL - 2
JO - Journal of Vision
JF - Journal of Vision
SN - 1534-7362
IS - 10
ER -