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Abstract:
While numerous previous studies investigated how feature-based attention modulates mean neural activity, little is known about effects of feature-based attention on connectivity between feature-selective regions and nodes of the dorsal attention network or of the default mode network. Here we used a block design with ultra-long trials lasting 3 minutes that alternated between color attention, motion attention and passive viewing, involving the same stimuli. This paradigm allowed for high-quality functional connectivity measurements free of confounds related to on- and offset effects of stimulus blocks. Functional connectivity was measured between visual regions V4 and V5/MT+ (responsive to color and motion, respectively) with nodes of the dorsal attention network (DAN) and of the default mode network (DMN). Attention to color versus motion enhanced the connectivity between DAN and V4 more than between DAN and V5/MT, revealing selective enhancement of connectivity depending on the attended feature. Conversely, color versus motion attention reduced the connectivity between DMN and V4 more than between DMN and V5/MT+, showing feature-selective reduction in connectivity. The results hence show that not only nodes of the DAN selectively modulate connectivity with specific visual regions depending on the attended feature, but that the same holds true for nodes of the DMN, yet with inversed sign. The current study raises a role of DMN, previously known to be involved in rest, mind wandering or inversely in attention to external features, to interact with visual regions in a selective manner during feature selective attention.
