Perc@tual and Motor Skills, 1977,44,837-838.
@ Perceptual and Motor Skills 1977
TWO-PULSE TEMPORAL RESOLUTION THRESHOLD IN THE PERIPHERAL VISUAL FIELD NAOYUKI OSAKA' Kyoto U~liuersify,Kyoto, Jafian Summary.--Using a 700-nm light-emitting diode, the minimum inter-pulse interval between rwo successively flashing pulses presented to 21 retinal loci along horizontal and vertical meridian were measured. The results showed interpulse interval changed as a W-shaped function of eccentricity on both meridians.
The minimum perceptible inter-pulse interval (IPI) becween two successively flashing pulses presented to the same retinal locus were investigated along the horizontal and the vertical meridian of the right eye. A Gap-light-emitting diode (LED: TLR-102)having diffused and homogeneous red light output with peak wavelength of 700 nm (half-width 100 nm) was placed in position along the hemispherical plane of the perimeter as a light source. The target had about 20 mL of luminance with rise and fall times shorter than .O1 msec. The duration of each pulse was fixed 100 msec. which had been controlled by digital preset timer with .Ol-rnsec. precision and logic programming module (Unitec, UDT306L, UL-101). A LED target subtending a visual angle of 47' was randomly presented to 2 1 retinal loci: fovea and 10, 20, 30, 40, and 50' eccentric to the fovea along both meridians. Using a method of limits, the subject was asked to judge the minimum inter-pulse interval which varied between 0 and 50 msec. in steps of 5-msec. units in DADAADAD order. Thus, each of the subjects performed 21 X 8 trials. After 10 min. of dark adaptation, the subject, with his
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3'0
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TEMPORAL
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2'0
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NASAL
RETINAL
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E C C E N T R I C I T Y . DEG
FIG. 1. Perceptible inter-pulse interval as a function of retinal eccentricity. Each point is based on 40 vials of five subjects. Vertical line shows standard deviation. 'Present address: Psychology Laboratories. Otemon-gakuin University, 230 Ai, Ibaraki. Osaka 567 Japan.
838
N.OSAKA
head resting on a chin-support, started the trial by pressing the trigger switch at his own pace while keeping fixation on a field surrounded with four just visible red lights. The means of the inter-pulse intervals as a function of eccentricity are plotted in Fig. 1. A three-way mixed analysis of variance showed that the main effect of eccentricity and the interaction of eccentricity X meridian were significant ( F ~ O=, 22.83, ~ ~ p < .001 and F10,40= 6.87, p < ,001, respectively). The main effect of meridian was, however, not significant (FIs4= 3.07). It is likely that the minimum inter-pulse interval varied as a W-shaped function of eccentricity on both meridians. The results are in good agreement with the data for the fovea obtained by Kietzman and Sutton ( 1968). Interestingly enough, the minimum inter-pulse interval increased in the fovea and decreased 20" eccentric to the fovea on both meridians. This may be inversely related to density functions of rods as well as cones. REFERENCE
K I E ~M. , L.,
& SUTIY)N,
S. The interpretation of two-pulse measures of remporal
resolution in vision. Vision Research, 1968, 8 , 287-302.
Accepted March Ib, 1977.
@ Perceptual and Motor Skills 1977
TWO-PULSE TEMPORAL RESOLUTION THRESHOLD IN THE PERIPHERAL VISUAL FIELD NAOYUKI OSAKA' Kyoto U~liuersify,Kyoto, Jafian Summary.--Using a 700-nm light-emitting diode, the minimum inter-pulse interval between rwo successively flashing pulses presented to 21 retinal loci along horizontal and vertical meridian were measured. The results showed interpulse interval changed as a W-shaped function of eccentricity on both meridians.
The minimum perceptible inter-pulse interval (IPI) becween two successively flashing pulses presented to the same retinal locus were investigated along the horizontal and the vertical meridian of the right eye. A Gap-light-emitting diode (LED: TLR-102)having diffused and homogeneous red light output with peak wavelength of 700 nm (half-width 100 nm) was placed in position along the hemispherical plane of the perimeter as a light source. The target had about 20 mL of luminance with rise and fall times shorter than .O1 msec. The duration of each pulse was fixed 100 msec. which had been controlled by digital preset timer with .Ol-rnsec. precision and logic programming module (Unitec, UDT306L, UL-101). A LED target subtending a visual angle of 47' was randomly presented to 2 1 retinal loci: fovea and 10, 20, 30, 40, and 50' eccentric to the fovea along both meridians. Using a method of limits, the subject was asked to judge the minimum inter-pulse interval which varied between 0 and 50 msec. in steps of 5-msec. units in DADAADAD order. Thus, each of the subjects performed 21 X 8 trials. After 10 min. of dark adaptation, the subject, with his
!:~m tw b/~ w
2
m
10
I-
y a w v =1
2
E
M 1P1
10
3'0
.'o
3'0
A
TEMPORAL
o:
o:
2'0
3 :
NASAL
RETINAL
4'0
A
A
:3
2'0
1'0
: .,'
SUPERIOR
:2
3 ' 0
a.'
4
INfERlOU
E C C E N T R I C I T Y . DEG
FIG. 1. Perceptible inter-pulse interval as a function of retinal eccentricity. Each point is based on 40 vials of five subjects. Vertical line shows standard deviation. 'Present address: Psychology Laboratories. Otemon-gakuin University, 230 Ai, Ibaraki. Osaka 567 Japan.
838
N.OSAKA
head resting on a chin-support, started the trial by pressing the trigger switch at his own pace while keeping fixation on a field surrounded with four just visible red lights. The means of the inter-pulse intervals as a function of eccentricity are plotted in Fig. 1. A three-way mixed analysis of variance showed that the main effect of eccentricity and the interaction of eccentricity X meridian were significant ( F ~ O=, 22.83, ~ ~ p < .001 and F10,40= 6.87, p < ,001, respectively). The main effect of meridian was, however, not significant (FIs4= 3.07). It is likely that the minimum inter-pulse interval varied as a W-shaped function of eccentricity on both meridians. The results are in good agreement with the data for the fovea obtained by Kietzman and Sutton ( 1968). Interestingly enough, the minimum inter-pulse interval increased in the fovea and decreased 20" eccentric to the fovea on both meridians. This may be inversely related to density functions of rods as well as cones. REFERENCE
K I E ~M. , L.,
& SUTIY)N,
S. The interpretation of two-pulse measures of remporal
resolution in vision. Vision Research, 1968, 8 , 287-302.
Accepted March Ib, 1977.
