Document Detail

Contrast and stimulus complexity moderate the relationship between spatial frequency and perceived speed: implications for MT models of speed perception.
MedLine Citation:
PMID:  22194317     Owner:  NLM     Status:  MEDLINE    
Area MT in extrastriate visual cortex is widely believed to be responsible for the perception of object speed. Recent physiological data show that many cells in macaque visual area MT change their speed preferences with a change in stimulus spatial frequency (N. J. Priebe, C. R. Cassanello, & S. G. Lisberger, 2003) and that this effect can accurately predict the dependence of perceived speed on spatial frequency demonstrated in a related psychophysical study (N. J. Priebe & S. G. Lisberger, 2004). For more complex compound gratings and high contrast stimuli, MT cell speed preferences show sharper tuning and less dependence on spatial frequency (Priebe et al., 2003), allowing us to predict that such stimuli should produce speed percepts that are less vulnerable to spatial frequency variations. We investigated the perceived speed of simple sine wave gratings and more complex compound gratings (formed from 2 sine wave components) in response to changes in contrast and spatial frequency. In all cases, high contrast stimuli appeared to translate more rapidly. In addition, high spatial frequencies appeared faster-the opposite effect to that predicted by changes in MT cell spatial frequency preferences. Complex grating stimuli were somewhat "protected" from the effect of spatial frequency (compared to simple gratings), as predicted. However, contrary to predictions, the effect of spatial frequency was larger in high (compared to low) contrast gratings. Our data demonstrate that the previously established links between changes in MT cells' speed preferences and human speed perception are more complex than first thought.
Kevin R Brooks; Thomas Morris; Peter Thompson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-12-22
Journal Detail:
Title:  Journal of vision     Volume:  11     ISSN:  1534-7362     ISO Abbreviation:  J Vis     Publication Date:  2011  
Date Detail:
Created Date:  2011-12-23     Completed Date:  2012-04-17     Revised Date:  2013-01-09    
Medline Journal Info:
Nlm Unique ID:  101147197     Medline TA:  J Vis     Country:  United States    
Other Details:
Languages:  eng     Pagination:  19     Citation Subset:  IM    
Macquarie University, Sydney, New South Wales, Australia.
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MeSH Terms
Contrast Sensitivity / physiology*
Motion Perception / physiology*
Neurons / physiology
Space Perception / physiology*
Visual Cortex / physiology*
Visual Perception / physiology

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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