Document Detail


Direction opponency, not quadrature, is key to the 1/4 cycle preference for apparent motion in the motion energy model.
MedLine Citation:
PMID:  20739550     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Sensitivity to visual motion is a fundamental property of neurons in the visual cortex and has received wide attention in terms of mathematical models. A key feature of many popular models for cortical motion sensors is the use of pairs of functions that are related by a 90 degrees phase shift. This phase relationship, known as quadrature, is the hallmark of the motion energy model and played an important role in the development of a class of model dubbed elaborated Reichardt detectors. For decades, the literature has supported a link between quadrature and the observation that motion detectors and human observers often prefer a 1/4 cycle displacement of an apparent motion stimulus that consists of a pair of sinusoidal gratings. We show that there is essentially no link between quadrature and this preference. Quadrature is neither necessary nor sufficient for a motion sensor to prefer 1/4 cycle displacement, and motion energy is not maximized for a 1/4 cycle step. Other properties of motion sensors are the key: the opponent subtraction of two oppositely tuned stages that individually have sinusoidal displacement tuning curves. Thus, psychophysical and neurophysiological data revealing a preference at or near 1/4 cycle displacement do not offer specific support for common quadrature or energy-based motion models. Instead, they point to a broader class of model.
Authors:
Nicolas Heess; Wyeth Bair
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  30     ISSN:  1529-2401     ISO Abbreviation:  J. Neurosci.     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-08-26     Completed Date:  2010-09-16     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  11300-4     Citation Subset:  IM    
Affiliation:
Neuroinformatics and Computational Neuroscience Doctoral Training Centre, Institute for Adaptive and Neural Computation, School of Informatics, University of Edinburgh, Edinburgh EH8 9AB, United Kingdom. n.m.o.heess@sms.ed.ac.uk
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MeSH Terms
Descriptor/Qualifier:
Attention* / physiology
Energy Transfer* / physiology
Models, Biological*
Motion Perception* / physiology
Photic Stimulation / methods*
Visual Cortex / physiology
Grant Support
ID/Acronym/Agency:
//Medical Research Council; //Wellcome Trust

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


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