title: Decoding pattern motion information in V1.
abstract: When two gratings drifting in different directions are superimposed, the resulting stimulus can be perceived as two overlapping component gratings moving in different directions or as a single pattern moving in one direction. Whilst the motion direction of component gratings is already represented in visual area V1, the majority of previous studies have found processing of pattern motion direction only from visual area V2 onwards. Here, we question these findings using multi-voxel pattern analysis (MVPA). In Experiment 1, we presented superimposed sinusoidal gratings with varying angles between the two component motions. These stimuli were perceived as patterns moving in one of two possible directions. We found that linear support vector machines (SVMs) could generalise across stimuli composed of different component motions to successfully discriminate pattern motion direction from brain activity in V1, V3A and hMT+/V5. This demonstrates the representation of pattern motion information present in these visual areas. This conclusion was verified in Experiment 2, where we manipulated similar plaid stimuli to induce the perception of either a single moving pattern or two separate component gratings. While a classifier could again generalise across stimuli composed of different component motions when they were perceived as a single moving pattern, its performance dropped substantially in the case where components were perceived. Our results indicate that pattern motion direction information is present in V1.
authors.affiliation: Berlin School of Mind and Brain, Humboldt Universität zu Berlin, Berlin, Germany; Department of Psychiatry and Psychotherapy, Campus Charite Mitte, Charité-Universitätsmedizin Berlin, Berlin, Germany; Berlin Center for Advanced Neuroimaging, Charité - Universitätsmedizin, Berlin, Germany. Electronic address: biancavankemenade@gmail.com.
authors.forename: Bianca M
authors.initials: BM
authors.lastname: van Kemenade
authors.affiliation: Department of Psychiatry and Psychotherapy, Campus Charite Mitte, Charité-Universitätsmedizin Berlin, Berlin, Germany; Berlin Center for Advanced Neuroimaging, Charité - Universitätsmedizin, Berlin, Germany; Department of Cognitive Science, Macquarie University, Sydney, Australia.
authors.forename: Kiley
authors.initials: K
authors.lastname: Seymour
authors.affiliation: Berlin Center for Advanced Neuroimaging, Charité - Universitätsmedizin, Berlin, Germany; Bernstein Center for Computational Neuroscience, Berlin, Germany.
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Christophel
authors.affiliation: Department of Psychiatry and Psychotherapy, Campus Charite Mitte, Charité-Universitätsmedizin Berlin, Berlin, Germany; Berlin Center for Advanced Neuroimaging, Charité - Universitätsmedizin, Berlin, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Rothkirch
authors.affiliation: Berlin School of Mind and Brain, Humboldt Universität zu Berlin, Berlin, Germany; Department of Psychiatry and Psychotherapy, Campus Charite Mitte, Charité-Universitätsmedizin Berlin, Berlin, Germany; Berlin Center for Advanced Neuroimaging, Charité - Universitätsmedizin, Berlin, Germany; Bernstein Center for Computational Neuroscience, Berlin, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Sterzer
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009038:Motion; D009039:Motion Perception / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D014793:Visual Cortex / Q000502:physiology*; D055815:Young Adult
keywords: Pattern motion; V1; fMRI