mussap-spatialproperties-1996.pdf (2.41 MB)
Spatial properties of filters underlying vernier acuity revealed by masking: evidence for collator mechanisms
journal contribution
posted on 1996-08-01, 00:00 authored by Alexander MussapAlexander Mussap, D M LeviModels of vernier acuity based on the differential response of oriented filters receive support from the finding that vernier threshold elevation peaks for grating mask orientations which are slightly different from the orientation of the vernier bars. We replicate this effect using long, abutting vernier bars, and masks which possess gaps up to 22.5' wide (Experiments 1 and 3); a surprising result considering that vernier acuity improves little for bars longer than 10'. To account for this we suggest the involvement of elongated mechanisms (referred to as collators or collectors) that "integrate" responses of numerous smaller filters along the axis of their common orientation. The collator model explains patterns of threshold elevation obtained with a variety of mask-vernier configurations. In particular, the model predicts that masks located midway between separated vernier bars will interfere with integrative processes occurring over the entire region encompassing both bars (Experiment 2). In confirmation of this prediction we find that centrally placed masks produce significant orientation-specific threshold elevation. In suggesting a contribution to vernier acuity from integrative mechanisms, our results, along with others, emphasize the importance of global processes in vernier acuity.
History
Journal
Vision researchVolume
36Issue
16Pagination
2459 - 2473Publisher
ElsevierLocation
Kidlington, Eng.Publisher DOI
Link to full text
ISSN
0042-6989eISSN
1878-5646Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
1996, ElsevierUsage metrics
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