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SUMMARY:How do we perceive motion direction? - Linda Bowns\, Nottingham Vi
 sual Neuroscience\, School of Psychology
DTSTART:20070605T120000Z
DTEND:20070605T130000Z
UID:TALK7277@talks.cam.ac.uk
CONTACT:Cordula Becker
DESCRIPTION: I will briefly introduce the idea of how we might extract mot
 ion using spatio-temporal energy. Spatio-temporal energy models of motion 
 involve breaking down moving patterns into simpler sinusoidal patterns tha
 t have their own motion\, and it is the spatio-temporal energy of these co
 mponents that determine the response of V1 neurons. This is an efficient m
 ethod of encoding pattern motion because for moving sinusoidal images\, al
 l measurements of the same velocity lie along a line in spatial frequency/
 temporal frequency space. I have been interested in how the spatio-tempora
 l energy of these simpler patterns might be combined to predict perceived 
 pattern motion direction. I will describe the two main combination rules: 
 the ‘intersection of constraints’ rule (IOC) and the ‘vector average
 ’ (VA). I will provide empirical evidence showing that the results suppo
 rting the vector average do not generalise. In addition\, David Alais and 
 myself have shown that both solutions can be simultaneously encoded. This 
 is curious given that they are thought to be mutually exclusive hypotheses
 . When perceived pattern motion is predicted by the vector average it may 
 be caused by underlying mechanisms that respond to either spatio-temporal 
 energy caused by distortion products\, or possibly by my implementation of
  the intersection of constraints rule that can also encode information cor
 responding to distortion products. This may explain why vector averaging i
 s not a general property and why both solutions ‘appear’ to be encoded
 .
LOCATION:Seminar Room (ground floor)\, Craik-Marshall Building
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