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Mark D. Lescroart, Xiaomin Yue, Kenneth Hayworth, Irving Biederman; Laterality effects in the LOC. Journal of Vision 2006;6(6):540. doi: 10.1167/6.6.540.
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© ARVO (1962-2015); The Authors (2016-present)
The lateral occipital complex (LOC), an area critical for object recognition (James et al., 2003), is defined by fMRI criteria as the region in which there exists a difference in the activation produced by intact and scrambled pictures of objects (Malach et al, 1995). To assess coarse retinotopy in the LOC, subjects viewed sequences of either intact or scrambled images presented in quadrants of the visual field while they maintained central fixation. The eccentricity and sizes of the images were designed to produce neural activity that would be confined to a single quadrant, based on single-unit receptive field tuning in macaque TEO (Ungerleider, 1991). Although there was significant activation (above baseline) from ipsilateral presentations, activation in the LOC in the hemisphere contralateral to the side of presentation was significantly greater than in the ipsilateral LOC. The differences in loci of activation between upper and lower visual fields were much less pronounced. The laterality effect was more marked in the lateral occipital cortex (LO) than in the posterior fusiform (pFs), a result consistent with the general finding of an increase in the complexity of the representation along the anterior-posterior axis of the LOC. Assuming a decrease in retinotopy from posterior to anterior along the ventral stream pathway, the LOC's homology with macaque stages would appear to be anterior to TEO (because of the absence of upper vs. lower field differences) and posterior to TE (assuming that activation in TE is invariant to side of presentation).
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