Abstract
The visual evoked potential (VEP) has been successfully applied to investigations of chromatic mechanisms. We summarize here our VEP investigations of the development of chromatic mechanisms from 1 week to 1 year of age and the subsequent maturation of the chromatic VEP waveforms that continues through puberty. In addition, we present new data on the aging of the chromatic response in a population ranging in age from 18 to 90 years. Visual evoked potentials were recorded to pattern-onset presentations of 0.5 and 1.0 cpd horizontal sinusoidal gratings. Patterns were composed of colors that were chosen to selectively activate the chromatic and achromatic mechanisms. Responses were also recorded to reversal presentations of achromatic gratings. The shapes of the chromatic waveforms change systematically and rapidly through the first year of life. These changes are complex and contrast with the early and simple changes seen for achromatic reversal responses. Chromatic onset waveforms continue to change shape slowly but dramatically during the next 12 years and don't appear as they do in the adult until puberty. In the aging population, the general shapes of the chromatic waveforms show little change. The majority of change in the chromatic waveforms is characterized predominantly by significant increases in latency. The relative stability of the shape and the systematic changes in latency of chromatic waveforms from puberty through the 9th decade of life suggests that age-matched norms can be developed for clinical application.
This work was supported by grants from the W.O Rodgers Fund, the Sanford Center for Aging at the University of Nevada, and the National Institutes on Aging.