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SUMMARY:Mechanism for analogous illusory motion perception in flies and hu
 mans - Adam Triabhall
DTSTART:20260306T140000Z
DTEND:20260306T150000Z
UID:TALK245515@talks.cam.ac.uk
CONTACT:Adam Triabhall
DESCRIPTION:This week we will discuss and debate a paper by Agrochao and c
 olleagues (2020).\n\nAbstract: “Visual motion detection is one of the mo
 st important computations performed by visual circuits. Yet\, we perceive 
 vivid illusory motion in stationary\, periodic luminance gradients that co
 ntain no true motion. This illusion is shared by diverse vertebrate specie
 s\, but theories proposed to explain this illusion have remained difficult
  to test. Here\, we demonstrate that in the fruit fly Drosophila\, the ill
 usory motion percept is generated by unbalanced contributions of direction
 -selective neurons’ responses to stationary edges. First\, we found that
  flies\, like humans\, perceive sustained motion in the stationary gradien
 ts. The percept was abolished when the elementary motion detector neurons 
 T4 and T5 were silenced. In vivo calcium imaging revealed that T4 and T5 n
 eurons encode the location and polarity of stationary edges. Furthermore\,
  our proposed mechanistic model allowed us to predictably manipulate both 
 the magnitude and direction of the fly’s illusory percept by selectively
  silencing either T4 or T5 neurons. Interestingly\, human brains possess t
 he same mechanistic ingredients that drive our model in flies. When we ada
 pted human observers to moving light edges or dark edges\, we could manipu
 late the magnitude and direction of their percepts as well\, suggesting th
 at mechanisms similar to the fly’s may also underlie this illusion in hu
 mans. By taking a comparative approach that exploits Drosophila neurogenet
 ics\, our results provide a causal\, mechanistic account for a long-known 
 visual illusion. These results argue that this illusion arises from archit
 ectures for motion detection that are shared across phyla” (Agrochao et 
 al.\, 2020).\n\nReference: Agrochao\, M.\, Tanaka\, R.\, Salazar-Gatzimas\
 , E.\, & Clark\, D. A. (2020). Mechanism for analogous illusory motion per
 ception in flies and humans. Proceedings of the National Academy of Scienc
 es\, 117(37)\, 23044–23053.
LOCATION:https://cam-ac-uk.zoom.us/j/92612577704?pwd=MUtqMjVQdXNmUTVIYjRkM
 G1NUW9GZz09
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