Global topological dominance in the left hemisphere

Abstract

A series of experiments with right-handers demonstrated that the left hemisphere (LH) is reliably and consistently superior to the right hemisphere (RH) for global topological perception. These experiments generalized the topological account of lateralization to different kinds of topological properties (including holes, inside/ outside relation, and ''presence vs. absence'') in comparison with a broad spectrum of geometric properties, including orientation, distance, size, mirror-symmetry, parallelism, collinearity, etc. The stimuli and paradigms used were also designed to prevent subjects from using various nontopological properties in performing the tasks of topological discrimination. Furthermore, task factors commonly considered in the study of hemispheric asymmetry, such as response latency vs. accuracy, vertical vs. horizontal presentation, detection vs. recognition, and simultaneous vs. sequential judgment, were manipulated to not be confounding factors. Moreover, left-handed subjects were tested and showed the right lateralization of topological perception, in the opposite direction of lateralization compared with right-handers. In addition, the functional magnetic resonance imaging measure revealed that only a region in the left temporal gyrus was consistently more activated across subjects in the task of topological discrimination, consistent with the behavioral results. In summary, the global topological dominance in the LH is well supported by the converging evidence from the variety of paradigms and techniques, and it suggests a unified solution to the current major controversies on visual lateralization.visual lateralization ͉ perception ͉ temporal gyrus ͉ holes ͉ inside/outside relation

Topological change disturbs object continuity in attentive tracking

“…The result revealed a major activation in the ATL (Talairach coordinates: −54, −8, −10; 52, −2, −24) (Fig. S1A and Table S1)], consistent with previous findings that the ATL is involved in topological perception (16,17).…”

Holes, objects, and the left hemisphere

“…The most notable theory is the one developed by Kosslyn et al (10,11), which proposes that the left hemisphere is more adept at processing categorical spatial relationships, whereas the right hemisphere is more efficient at processing coordinate spatial relationships. As reviewed by Wang et al (6), there are inconsistencies in the existing literature on hemispheric lateralization of visual functions, and they suggested that the topological account provides a unified solution to characterization of the hemispheric asymmetry in visual shape perception. Although a claim of a unified model requires more theoretical as well as empirical support, the topological model does provide a coherent account and precise predictions about the functional lateralization of visual shape perception.…”

“…With functional magnetic resonance imaging (fMRI) measures, Wang et al (6) also searched for the potential neural correlates of enhanced topological sensitivity. Two sets of fMRI experiments converge to a region in the left temporal lobe, a site somewhat anterior to category-selective visual cortical sites.…”

A comparative psychophysical approach to visual perception in primates

“…Functional asymmetry between left and right hemispheres in global-local processing has been reported in humans (e.g. Wang et al 2007). According to this hypothesis, different degrees of hemispheric lateralization may correlate with differences in performance among species.…”