To test the effect of tactile motion on visual perception, adjacent rows of pins vibrated in rapid succession, creating the sensation of a tactile object sweeping up or down the subjects' fingertips. After 10 seconds of this stimulus, the monitor displayed a static pattern of horizontal stripes. Contrary to the prevailing assumption that vision always trumps touch, subjects perceived the stripes as moving in the opposite direction to the moving tactile stimulus.
[Click here to view demos of the motion stimuli used in this study: http://web.mit.edu/~tkonkle/www/CrossmodalMAE.html]
"Aftereffects were once thought to reflect fatigue in the brain circuits," said Konkle, "but we now know that pools of neurons are continuously coding motion information and recalibrating the brain to its sensory environment. Our neurons are not tired, they are constantly adapting to the world around us."
Recent studies have found that a region of the visual cortex known as MT or V5 long thought to play a major role in the perception of motion may also process tactile motion. Moore's team intends to explore this brain region in future studies to determine whether it contributes to these cross-modal motion aftereffects.
"Neuroscientists study perceptual illusions because they help reveal how the brain gives rise to conscious experience," Moore said. "We don't experience the world through isolated senses, and our data support the emerging view that the brain is organized for cross talk among different sensory modalities."
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| Contact: Julie Pryor jpryor@mit.edu 617-715-5397 McGovern Institute for Brain Research Source:Eurekalert |