Our vision takes into account spatial contexts in constructing the visual world in the mind. With respect to motion, spatial contexts include an illusion of induced motion, in which a static figure appears to move opposite to the motion of a surrounding figure. No study has ever directly compared this psychological phenomenon with brain activity. This phenomenon is linked to our fundamental information processing by which a differently moving region is extracted from a larger surround, and thus understanding of induced motion and its neural counterpart will open a gate to the fundamental understandings of our vision.
Post-doctoral Fellow Hiromasa Takemura, Associate Professor Ikuya Murakami at the Graduate School of Arts and Sciences, the University of Tokyo, and others carried out a functional brain imaging experiment, identifying the neural correlate of induced motion perception in the cerebral cortex of the human experiencing induced motion. In a concentric stimulus, its surrounding region contained a moving figure. Given a static figure in the central region, an observer would perceive induced motion. When the central stimulus is moving at the very speed at which illusory induced motion is just canceled, this stimulus is physically moving but subjectively stationary. The brain region that was minimally activated by this stimulus, namely the neural correlate of induced motion, was identified in the cerebral cortex.
Making use of the perceptual characteristics determined in this study in relation to spatial contexts will make it possible to devise such future apparatus as illusion-based spectacles that can boost visual sensitivity through the power of visual illusions. Understanding illusions and their neural bases are important studies that can lead to sensitivity enhancement.
Paper: “Neural correlates of induced motion perception in the human brain,” Journal of Neuroscience Online Edition: 2012/10/10 (USA Eastern time), doi: 10.1523/JNEUROSCI.0570-12.2012 Article link
Source: University of Tokyo