Document Detail


Attenuation of Mach bands by adjacent stimuli.
MedLine Citation:
PMID:  6576350     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Pronounced bright and dark bands are seen at the bright and dark edges of half-shadows and similar distributions of illumination. These are the so-called Mach bands. A pair of vertical Mach bands was generated with a ramp pattern in the central strip of a horizontal tripartite oscilloscope display. This pattern consisted of two uniform fields (one of low luminance, one of high luminance) joined by a gradient of uniform slope. The upper and lower strips were uniform throughout. A coupled pair of pointers could be displayed in these two strips and adjusted by the observer to match the apparent location and width of either of the Mach bands in the central strip. Insertion of a vertical bar in the central strip nearby and on either side of the ramp attenuates the corresponding Mach band. The closer the bar is to the Mach band, the stronger the attenuation. The attenuation is nearly independent of the sign of the contrast of the bar, but it does depend upon the magnitude and sharpness of the contrast. Also, the attenuation is independent of the width of the bar; a narrow line is as effective as a broad bar of the same contrast. No net luminance change is required; a bipolar stimulus with equal parts above and below the mean is as effective as a monopolar stimulus. These results point to two competing physiological mechanisms with different spatial sensitivities--one that generates Mach bands and one that attenuates them.
Authors:
F Ratliff; N Milkman; N Rennert
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  80     ISSN:  0027-8424     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  1983 Jul 
Date Detail:
Created Date:  1983-09-09     Completed Date:  1983-09-09     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  4554-8     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Darkness
Humans
Light
Oscillometry
Photic Stimulation
Vision, Ocular*
Visual Perception*
Grant Support
ID/Acronym/Agency:
S07 RR07065/RR/NCRR NIH HHS
Comments/Corrections

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