Purchase this article with an account.
AM Norcia, V Sampath, C Hou, F Pei; Contour Integration in Human Infants . Invest. Ophthalmol. Vis. Sci. 2002;43(13):3993.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose:The extraction of the bounding contours of objects is an important component of shape perception. Synthetic contours composed of strings of Gabor patches can be used to isolate the contribution of long-range interactions between local elements along the contours. Here we asked whether infants can detect collinearity in Gabor-defined contours. Methods:Visual Evoked Potentials were recorded from 11-39 week old infants (mean age is 26 wks) and 12 adults. The stimulus consisted of 11 circular Gabor-defined contours, each composed of 12 Gabor patches (spatial frequency of 1.5cpd, envelope SD of 0.18 deg; contrast 80%; 3 wavelength spacing between centers of elements). The test condition consisted of a circular configuration where the patches were collinear, alternated with a pinwheel configuration. The control condition consisted of a clockwise-facing pinwheel that alternated with a counter-clockwise-facing pinwheel. The amount of local apparent motion was equal (30 deg) in the test and control conditions. Spectral analysis was performed on the first 9 harmonics of the stimulus frequency of 1 Hz. Results: The circle/pinwheel test condition elicited both odd and even harmonic components, while the pinwheel/pinwheel configuration elicited only even harmonic components in both adults and infants. The odd-harmonic components were a result of the response being larger to a transition from the circle to the pinwheel compared to the response generated by the transition from the pinwheel to the circle. The infant odd-harmonic response was substantially less prominent than that of the adult and the infant waveforms were much smoother and delayed in latency compared to those of the adults. Conclusion:Small but statistically reliable configuration-specific responses to Gabor-defined contours can be recorded in infants less than one year of age. In our task, this requires sensitivity to both local orientation changes and to longer-range correlations in stimulus orientation such as those found along extended contours.
This PDF is available to Subscribers Only