PT  - JOURNAL ARTICLE
AU  - Helena X. Wang
AU  - Elisha P. Merriam
AU  - Jeremy Freeman
AU  - David J. Heeger
TI  - Motion Direction Biases and Decoding in Human Visual Cortex
AID  - 10.1523/JNEUROSCI.1034-14.2014
DP  - 2014 Sep 10
TA  - The Journal of Neuroscience
PG  - 12601--12615
VI  - 34
IP  - 37
4099  - http://www.jneurosci.org/content/34/37/12601.short
4100  - http://www.jneurosci.org/content/34/37/12601.full
SO  - J. Neurosci.2014 Sep 10; 34
AB  - 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.