Document Detail


What a difference a parameter makes: a psychophysical comparison of random dot motion algorithms.
MedLine Citation:
PMID:  19336240     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Random dot motion (RDM) displays have emerged as one of the standard stimulus types employed in psychophysical and physiological studies of motion processing. RDMs are convenient because it is straightforward to manipulate the relative motion energy for a given motion direction in addition to stimulus parameters such as the speed, contrast, duration, density, aperture, etc. However, as widely as RDMs are employed so do they vary in their details of implementation. As a result, it is often difficult to make direct comparisons across studies employing different RDM algorithms and parameters. Here, we systematically measure the ability of human subjects to estimate motion direction for four commonly used RDM algorithms under a range of parameters in order to understand how these different algorithms compare in their perceptibility. We find that parametric and algorithmic differences can produce dramatically different performances. These effects, while surprising, can be understood in relationship to pertinent neurophysiological data regarding spatiotemporal displacement tuning properties of cells in area MT and how the tuning function changes with stimulus contrast and retinal eccentricity. These data help give a baseline by which different RDM algorithms can be compared, demonstrate a need for clearly reporting RDM details in the methods of papers, and also pose new constraints and challenges to models of motion direction processing.
Authors:
Praveen K Pilly; Aaron R Seitz
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2009-03-29
Journal Detail:
Title:  Vision research     Volume:  49     ISSN:  1878-5646     ISO Abbreviation:  Vision Res.     Publication Date:  2009 Jun 
Date Detail:
Created Date:  2009-06-03     Completed Date:  2009-12-14     Revised Date:  2011-08-01    
Medline Journal Info:
Nlm Unique ID:  0417402     Medline TA:  Vision Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  1599-612     Citation Subset:  IM    
Affiliation:
Department of Cognitive and Neural Systems, Center for Adaptive Systems, Boston University, 677 Beacon St., Boston, MA 02215, United States. advait@cns.bu.edu
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Adult
Algorithms
Contrast Sensitivity / physiology
Female
Humans
Male
Motion Perception / physiology*
Photic Stimulation / methods
Psychophysics
Young Adult
Grant Support
ID/Acronym/Agency:
R01-DC02852/DC/NIDCD NIH HHS; R21 EY017737-01/EY/NEI NIH HHS; R21-EY017737/EY/NEI NIH HHS
Comments/Corrections

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