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Lior Bugatus, Kevin Weiner, Kalanit Grill-Spector; Task modulates category selectivity along a gradient from occipitotemporal cortex to prefrontal cortex in word- and face-selective regions. Journal of Vision 2015;15(12):1170. doi: 10.1167/15.12.1170.
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© ARVO (1962-2015); The Authors (2016-present)
The human brain contains separate functional networks constituting of multiple regions across occipital, temporal, and prefrontal cortices that are involved in processing faces and words. It is hypothesized that regions in occipitotemporal cortex process visual attributes of these stimuli and regions in the prefrontal cortex are involved with higher cognitive functions such as selective attention or working memory. However, it is unknown whether task and stimuli differentially affect responses of regions within these networks. Here we addressed this question by scanning 9 subjects using fMRI while they viewed stimuli from five categories: faces, bodies, houses, cars, and pseudo-words. Subjects performed in the same session three tasks in separate runs, and task order was counterbalanced across subjects. Oddball: subjects detected a randomly presented phase-scrambled image. Working memory: subjects indicated whether a stimulus repeated after an intervening image. Selective attention: subjects viewed superimposed images from two categories, attended to one stimulus category and reported when the attended stimulus was flipped upside-down. Word- and face-selective regions of interest in analogous anatomical locations were identified independently in each subject. Our analysis found a differential effect of task on stimulus selectivity across category-selective regions (task by region interaction, F(8,184) = 2.68, p = 0.008). Specifically, category-selectivity in lateral occipital cortex regions was similar across tasks, but was moderately increased in ventral temporal regions during the working memory task. In prefrontal cortex, however, the working memory task had a significant effect on category-selectivity: there was prominent face- and word-selectivity during the working memory task, but insignificant selectivity during the oddball and selective attention tasks. Together, these results reveal a gradient of selectivity that is modulated differentially by task, suggesting that the multiplicity of face- and word-selective regions may be related to task-relevant functional differences of individual components in these functional networks.
Meeting abstract presented at VSS 2015
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