The effect of aging on the orientational selectivity of the human visual system.

Leventhal et al. (Science, 2003, 300(5620), 812-815) reported that orientation selectivity of V1 neurons was significantly reduced in older macaque monkeys, which suggests that mechanisms that encode orientation in humans may become more broadly tuned in old age. We examined this hypothesis in two experiments that used sine-wave masking and notched-noise masking to estimate the bandwidth of orientation-selective mechanisms in younger (age approximately 23 years) and older (age approximately 68 years) human adults. In both experiments, the orientation selectivity of masking was essentially identical in younger and older subjects.