Perceptual Experience of Visual Motion Activates hMT+ Independently From the Physical Reality: fMRI Insights From the Looming Pinna Figure.
The human motion processing area, hMT+, has been labeled the critical neural area for processing of real and illusory visual motion in radial 2D patterns. However, the activation in hMT+ during perception of illusory rotation in the looming double-circular Pinna Figure (PF) generated in 3D space has not been observed yet. To do so, an optic-flow like motion of rings (looming) in PF was generated on a computer screen. A psychophysically precise nulling procedure allowed quantifying the individual amount of the perceived illusory rotation in PF (PI) for each participant. The interpolation of the individual illusory motion parameters created a subjectively non-rotating PF and a physically rotating control stimulus of identical rotary strength as the PI. The physically rotating control was a double-circular figure which diverged from PF only in its arrangement of luminance gradients. In a 3-Tesla scanner, participants were presented with a random order of rotating and non-rotating figures (illusory, real, no rotation, and nulled PI). Both types, illusory and real rotation, when equal in perceptual strength for the observer, were found to be processed by hMT+.
Faculty of Psychology and Neurosciences, Maastricht University, Netherlands.
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Budnik
Department of Psychiatry and Psychotherapy, Charité Campus Mitte, Charité-Universitätsmedizin Berlin, Germany.
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Hindi-Attar
Experimental Psychology and Cognitive Science, University Giessen, Germany.
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Hamburger
Facoltà di Lingue e Letterature Straniere, Università di Sassari, Italy.
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Pinna
Medical Physics, Department of Diagnostic Radiology, University Hospital Freiburg, Germany.
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Hennig
Biomedical Magnetic Resonance, Otto-von-Guericke University, Magdeburg, Germany.
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Speck
3D; Pinna Illusion (PI); Pinna-Figure (PF); double-circular figure; equalized perceptual strength; fMRI 3T; functional brain imaging; hMT+; looming; luminance gradients; motion interpolation; motion parameter; nulling procedure; radial 2D figure; real rotation; subjective illusory rotation