![]() ![]() ![]() ![]() Cortical gradients provide a new tool for understanding patterns of hemispheric specialisation, since networks with lateralised connectivity will occupy different positions along these gradients in the left (LH) and right hemispheres (RH). These gradients capture similarities in connectivity patterns across disparate areas of the cortex (Bressler and Menon 2010 Margulies et al. Lateralization of function may reflect differences in connectivity between control and heteromodal regions in LH, and attention and visual regions in RH.Ĭontemporary accounts of brain organisation conceptualise cognition as reflecting interactions of large-scale networks of brain regions, organised in a systematic fashion along cortical gradients. In contrast, when a dorsal attention subnetwork was closer to the heteromodal end of the principal gradient in RH, participants showed better visual reasoning. One frontotemporal control subnetwork was linked to individual differences in semantic cognition: when it was nearer heteromodal DMN on the principal gradient in LH, participants showed more efficient semantic retrieval-and this network also showed a strong hemispheric difference in response to semantic demands but not working memory load in a separate study. LH showed a higher overall principal gradient value, consistent with its role in heteromodal semantic cognition. We then extracted the principal gradient of connectivity for each participant, tested which networks showed significant hemispheric differences on the gradient, and regressed participants’ behavioural efficiency in tasks outside the scanner against interhemispheric gradient differences for each network. ![]() We collected resting-state fMRI and semantic, working memory and non-verbal reasoning performance in 175 + healthy volunteers. This study characterised hemispheric differences in the position of large-scale cortical networks along the principal gradient, and their functional significance. Functional homotopy is strongest in sensorimotor areas, and weakest in heteromodal cortices, suggesting there may be differences between the left and right hemispheres (LH/RH) in the principal gradient, especially towards its apex. Decomposition of whole-brain functional connectivity patterns reveals a principal gradient that captures the separation of sensorimotor cortex from heteromodal regions in the default mode network (DMN). ![]()
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