Don't Overreact to this! Over-reactivity of the M-pathway in Older Adults

[摘要] The role of aging on cognitive decline has been looked at with a great deal of interest over the past few decades. Mainly, the aging literature has focused heavily on the impact of aging on memory and cognitive resources. However, one area of literature that remains underdeveloped has been the role on how aging affects the cognitive processes of vision, more specifically how aging changes the mutually inhibitory processes of the magnocellular (M) and parvocellular (P) pathways. Therefore, in order to test how aging affects these two visual pathways, we implemented techniques known to hinder or bolster the M-pathway in younger adults with older adults. In Experiment 1, we tested if the inhibition of the M-pathway with a pulsed pedestal design also occurs with older adults. In this task, we had younger and older adults perceive low and high spatial frequency gabors with either a pulsed or steady visual pedestal. In Experiment 2, we examined if the connection between the M-pathway and action processing found in younger adults changes with age. To do so, we adapted the same design but with action and non-action oriented objects instead of gabors. Across these two experiments, older adults showed a greater deficit in processing low spatial frequency gabors and action objects under the pulsed pedestal condition compared to younger adults. In Experiment 3, we examined if placing the hands proximal to visual images, which facilitates M-pathway processing in younger adults, also occurs for older adults. Here we found that older adults showed the opposite effect; greater advantage for low spatial frequency Gabors compared to younger adults when the hands were proximal. The data across all three experiments suggest that older adults may have overactive M-pathways, with larger deficits when the M-pathway is inhibited and larger benefits when the M-pathway is bolstered.

[学科分类] 眼科学