Abstract View

THE TILT AFTEREFFECT IS QUANTITATIVELY CONSISTENT WITH ADAPTATION-INDUCED CHANGES OF ORIENTATION TUNING OBSERVED IN VISUAL CORTEX. D.Z.Jin*; V.Dragoi; M.Sur; S.Seung Dept. Brain & Cognitive Sci, MIT, Cambridge, MA, USA The tilt aftereffect (TAE) is a striking visual illusion in which prolonged adaptation to an oriented visual stimulus causes subsequent stimuli to appear rotated away from the adapting orientation. Explaining this and other aftereffects in terms of neural mechanisms has been an important outstanding problem. Historically, a popular explanation of the TAE has been a hypothesized relative suppression of neurons tuned to the adapting orientation. Recent physiological studies have identified another important factor: the preferred orientations of V1 neurons repulsively shift away from the adapting orientation. Here we construct a population coding model that includes both factors, and show that the repulsive shift of the preferred orientations is necessary for quantitatively explaining the TAE. According to the model, the TAE is indeed caused by the relative suppression of the neural responses. However, it is substantially weakened by the preferred orientation shift. The relative suppression and the repulsive shift together lead to a TAE that is quantitatively consistent with the psychophysical data. Suppression alone would produce a TAE that is more pronounced than that observed. We suggest that the visual system uses the repulsive shift of the preferred orientations to reduce the perceptual error in orientation that could be induced by neural response suppression. Our population model of the TAE suggests a strategy that can also be useful for understanding other perceptual aftereffects, such as the motion aftereffect and the spatial frequency aftereffect. Support Contributed By: Howard Hughes Medical Institute (D.Z.J and H.S.S), the McDonnell-Pew Foundation (V.D.) and the NIH (M.S.) Citation: D.Z. Jin, V. Dragoi, M. Sur, S. Seung. THE TILT AFTEREFFECT IS QUANTITATIVELY CONSISTENT WITH ADAPTATION-INDUCED CHANGES OF ORIENTATION TUNING OBSERVED IN VISUAL CORTEX. Program No. 266.11. 2003 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2003. Online.