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Differential neural activation for camouflage detection task in Field-Independent and Field-Dependent individuals: Evidence from fMRI

Rajagopalan, Janani, Modi, Shilpi, Kumar, Pawan, Khushu, Subash, Mandal, Manas K
Journal of biosciences 2015 v.40 no.5 pp. 909-919
cerebellum, cognition, cortex, humans, magnetic resonance imaging, people, photographs, t-test, thalamus
It is not clearly known as to why some people identify camouflaged objects with ease compared with others. The literature suggests that Field-Independent individuals detect camouflaged object better than their Field-Dependent counterparts, without having evidence at the neural activation level. A paradigm was designed to obtain neural correlates of camouflage detection, with real-life photographs, using functional magnetic resonance imaging. Twenty-three healthy human subjects were stratified as Field-Independent (FI) and Field-Dependent (FD), with Witkin’s Embedded Figure Test. FIs performed better than FDs (marginal significance; p=0.054) during camouflage detection task. fMRI revealed differential activation pattern between FI and FD subjects for this task. One sample T-test showed greater activation in terms of cluster size in FDs, whereas FIs showed additional areas for the same task. On direct comparison of the two groups, FI subjects showed additional activation in parts of primary visual cortex, thalamus, cerebellum, inferior and middle frontal gyrus. Conversely, FDs showed greater activation in inferior frontal gyrus, precentral gyrus, putamen, caudate nucleus and superior parietal lobule as compared to FIs. The results give preliminary evidence to the differential neural activation underlying the variances in cognitive styles of the two groups.