title: Motion direction biases and decoding in human visual cortex.
abstract: Functional magnetic resonance imaging (fMRI) studies have relied on multivariate analysis methods to decode visual motion direction from measurements of cortical activity. Above-chance decoding has been commonly used to infer the motion-selective response properties of the underlying neural populations. Moreover, patterns of reliable response biases across voxels that underlie decoding have been interpreted to reflect maps of functional architecture. Using fMRI, we identified a direction-selective response bias in human visual cortex that: (1) predicted motion-decoding accuracy; (2) depended on the shape of the stimulus aperture rather than the absolute direction of motion, such that response amplitudes gradually decreased with distance from the stimulus aperture edge corresponding to motion origin; and 3) was present in V1, V2, V3, but not evident in MT+, explaining the higher motion-decoding accuracies reported previously in early visual cortex. These results demonstrate that fMRI-based motion decoding has little or no dependence on the underlying functional organization of motion selectivity.
authors.affiliation: Center for Neural Science and Department of Psychology, New York University, New York, New York 10003, and.
authors.forename: Helena X
authors.identifier: http://orcid.org/0000-0001-9180-2516
authors.initials: HX
authors.lastname: Wang
authors.affiliation: Center for Neural Science and Department of Psychology, New York University, New York, New York 10003, and.
authors.forename: Elisha P
authors.identifier: http://orcid.org/0000-0003-2787-566X
authors.initials: EP
authors.lastname: Merriam
authors.affiliation: Center for Neural Science and Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Freeman
authors.affiliation: Center for Neural Science and Department of Psychology, New York University, New York, New York 10003, and david.heeger@nyu.edu.
authors.forename: David J
authors.identifier: http://orcid.org/0000-0002-3282-9898
authors.initials: DJ
authors.lastname: Heeger
mesh_terms: D000328:Adult; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D011597:Psychomotor Performance / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*; D055815:Young Adult
keywords: coarse-scale bias; direction preference; fMRI; motion decoding; multivariate classification; visual cortex