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Electrophysiological Evidence for Adult Age Differences in Orientation Discrimination

Li, Xuan
http://rave.ohiolink.edu/etdc/view?acc_num=akron1512732686486329

Abstract Details

2017, Doctor of Philosophy, University of Akron, Psychology-Adult Development and Aging.
Older adults show age-related declines in orientation discrimination ability on low-contrast stimuli (Betts, Sekuler, & Bennett, 2007) and also high-contrast stimuli when using a more difficult psychophysical method (Li, Allen, Lien, & Yamamoto, 2017). In the present study, we employed event-related potential (ERP) recordings and the diffusion model (Ratcliff, 1978) to investigate whether the aging effect in the processing of orientation discrimination would occur during early-stage visual sensory processing (Experiment 1), during attention stage (Experiment 2) or during late-stage decision-making (Experiment 3) using healthy younger- and older-adult samples. Experiment 1 showed that early visual processing and the ability to distinguish different stimulus orientations as measured by behavioral performance was preserved in older adults. Older adults utilized more top-down control resources to compensate for the early visual processing deficits. Experiment 2 used a cue-target paradigm designed to measure the ability to allocate spatial attention with the N2pc ERP component. No cue-related lateralization of mental processes was found with peripheral cues. Older adults were more vulnerable to more effortful attention shifting with central cues and showed a contralateral delayed activity. These results suggested that older adults showed declines in top-down control of effortful attention shifting. In Experiment 3, a mixed orientation and phase discrimination task with a manipulation of stimulus contrast levels was performed. We found that the stimulus-locked P3 and 240-280 ms ERP components were well linked to the manipulation of stimulus contrast levels on the orientation discrimination task as well as behavioral measures and parameters estimated from the diffusion model. This suggested that the P3 and 240-280 ERP components were associated with the top-down control of evidence accumulation in perceptual decision making with a specific purpose for discriminating orientations. Older adults showed age-related declines in the modulation effect of stimulus contrasts on these two components. These results suggest that age differences in orientation discrimination ability did not occur during early visual process, but were present during the evidence accumulation process of perceptual decision making.
Philip Allen, PhD (Advisor)
Kevin Kaut, PhD (Committee Member)
Eric Allard, PhD (Committee Member)
Mei-Ching Lien, PhD (Committee Member)
Malena Espanol, PhD (Committee Member)
203 p.
Gerontology; Psychology
aging; perception; ERPs; Diffusion model; orientation discrimination

Recommended Citations

Citations

  • Li, X. (2017). Electrophysiological Evidence for Adult Age Differences in Orientation Discrimination [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1512732686486329

    APA Style (7th edition)

  • Li, Xuan. Electrophysiological Evidence for Adult Age Differences in Orientation Discrimination. 2017. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1512732686486329.

    MLA Style (8th edition)

  • Li, Xuan. "Electrophysiological Evidence for Adult Age Differences in Orientation Discrimination." Doctoral dissertation, University of Akron, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1512732686486329

    Chicago Manual of Style (17th edition)

akron1512732686486329
152
© 2017, all rights reserved.
This open access ETD is published by University of Akron and OhioLINK.