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Nadine Hummel, Virginia Flanagin; Direction discrimination of self motion consistent optic flow stimuli in multisensory integration cortices.. Journal of Vision 2015;15(12):863. doi: 10.1167/15.12.863.
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© ARVO (1962-2015); The Authors (2016-present)
Introduction When we move, optic flow generated on our retina, provides information about the speed and direction of our motion. Conversely, self-motion consistent optic flow presented to a stationary observer can evoke the perception of self motion, or vection. Patterns of activity in primary and higher visual areas can be used to decode information about the orientation and motion direction of visual stimuli. Self-motion consistent optic flow stimuli activate additional regions of the parietal cortex involved in multisensory integration of visual and vestibular information, but it is not yet clear whether direction sensitivity also exists there. Here we analyze activation patterns in these regions, during the presentation of self motion consistent optic flow stimuli. Methods Twenty-six subjects judged their heading direction based on self motion consistent optic flow stimuli in a 2 AFC paradigm, during fMRI. Brain activation patterns of eight heading directions in the fronto-orthogonal plane were evaluated using both univariate and pattern classification approaches. Functional localizers were used to identify area MT/MST and vection sensitive parietal regions. Results The univariate analysis revealed different BOLD levels for the eight heading directions throughout the dorsal visual stream. This included primary, as well as higher visual areas, parietal regions and some frontal regions. Cardinal and oblique directions showed differential activation within these regions. In a searchlight analysis, the stimuli were successfully classified within the same regions of the brain. Region-of-interest analyses revealed that area MT/MST, as well as the vection sensitive intraparietal sulcus show reliable pattern discrimination of the eight heading directions. Discussion Our results show that direction sensitivity for self motion consistent optic flow exists in primary as well as in higher visual areas. Heading direction is successfully decoded in brain regions involved in visuo-vestibular integration. This provides important insights towards an understanding of human navigation in space.
Meeting abstract presented at VSS 2015
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