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Terri L. Lewis, Dave Ellemberg, Daphne Maurer, Bryan Lee, Henry P. Brent, Alex V. Levin; The effects of early pattern deprivation on the development of the ability to detect local motion and to discriminate its velocity. Journal of Vision 2002;2(7):25. doi: https://doi.org/10.1167/2.7.25.
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Purpose. To measure the effect of early pattern deprivation on the development of sensitivity to detect the presence of motion and to discriminate velocity.
Methods. Subjects were patients treated for bilateral congenital cataract (duration of deprivation = 3.3 – 6.2 months; M = 4.4 mo), patients treated for unilateral congenital cataract who had patched their nondeprived eye 2 – 10 hrs/day throughout early childhood (duration of deprivation = 2.0 – 8.2 mo; M = 4.5 mo), and comparably aged normal controls (n = 9/grp). Subjects were at least 5 yrs old at the time of the test. We used a 10 deg Gabor and the method of limits to determine the minimum velocity required to detect movement. We used 10 × 10 deg patches of 1c/deg sine-wave gratings and a 2-alternative temporal forced-choice staircase procedure to measure the velocity that was just noticeably faster than 6 deg/sec.
Results. One-way ANOVAs revealed that both unilaterally (p < 0.01) and bilaterally (p = 0.05) deprived patients needed a significantly greater velocity than controls in order to detect movement of the Gabor's carrier grating, with no significant difference between patient groups (p > 0.20). Patients did not detect the movement until the velocity was about double that required for the control subjects. However, patients had normal velocity discrimination thresholds (p > 0.40), with all groups requiring about a 34% increase in velocity to detect that the sine wave was moving faster than 6 deg/sec.
Conclusions. Early pattern deprivation adversely affects the mechanisms underlying motion detection but, at least under some conditions, not those involved in velocity discrimination. The results suggest that early visual input plays different roles in the development of different aspects of the processing of local motion.
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