Decoding the Direction of Bistable Illusory Motion from Source-Reconstructed MEG Signals

Abstract

Motion perception involves both bottom–up sensory processing and top–down perceptual interpretation. Using magnetoencephalography frequency tagging and source-space multivariate pattern analysis, we decoded the perceived direction of both real and bistable apparent motion from cortical activity in 11 human participants (six males, five females). Real motion direction was decoded with near-ceiling accuracy across frequencies in both whole-brain and visual cortex analyses, whereas apparent motion direction was decoded just above chance from the visual cortex (56.0%, p = 0.011, Cohen’s d = 0.94) when combining the 5 and 7.5 Hz harmonics. Activation patterns showed a larger relative hMT+ contribution for apparent than real motion, and cross-classification did not generalize direction information between conditions. These results identify a measurable cortical signature of subjective motion direction but also show that it is relatively diffuse and only weakly bound to the retinotopic cortex.