Abstract
Attention facilitates the processing of task-relevant visual information and suppresses interference from task-irrelevant information. Modulations of neural activity in visual cortex depend on attention, and likely result from signals originating in fronto-parietal and cingulo-opercular regions of cortex. Here, we tested the hypothesis that attentional facilitation of visual processing is accomplished in part by changes in how brain networks involved in attentional control interact with sectors of V1 that represent different retinal eccentricities. We measured the strength of background connectivity between fronto-parietal and cingulo-opercular regions with different eccentricity sectors in V1 using functional MRI data that were collected while participants performed tasks involving attention to either a centrally presented visual stimulus or a simultaneously presented auditory stimulus. We found that when the visual stimulus was attended, background connectivity between V1 and the left frontal eye fields (FEF), left intraparietal sulcus (IPS), and right IPS varied strongly across different eccentricity sectors in V1 so that foveal sectors were more strongly connected than peripheral sectors. This retinotopic gradient was weaker when the visual stimulus was ignored, indicating that it was driven by attentional effects. Greater task-driven differences between foveal and peripheral sectors in background connectivity to these regions were associated with better performance on the visual task and faster response times on correct trials. These findings are consistent with the notion that attention drives the configuration of task-specific functional pathways that enable the prioritized processing of task-relevant visual information, and show that the prioritization of visual information by attentional processes may be encoded in the retinotopic gradient of connectivty between V1 and fronto-parietal regions.
Highlights
Cognitive control influences visual processing at the earliest stages of the visual system
Studies using background connectivity to characterize how connectivity among visual areas is modified by task factors have suggested that task-dependent changes in background connectivity may reflect the formation of task-dependent functional pathways for prioritized information transfer between brain regions (AlAidroos et al, 2012; Norman-Haignere et al, 2012)
This interpretation is further supported by other studies that have found that retinotopic patterns of background connectivity within and between early visual areas are related to performance on visual attention tasks (Haynes et al, 2005), as well as by studies showing that background connectivity between early visual cortex and areas that are involved in attentional control depends on task factors (Ebisch et al, 2013)
Summary
Cognitive control influences visual processing at the earliest stages of the visual system. Connectivity Results We hypothesized that the retinotopic patterns of background connectivity between V1 and control network nodes would differ between attention to visual vs auditory target modalities. Reported results are significant at p < 0.05, FWE-corrected using Bonferroni correction These analyses revealed significant two-way interaction effects of target modality and eccentricity on background connectivity with V1 for the control network nodes with coordinates in the left frontal cortex near the FEF (F6,84 = 5.20; p = 0.005, FWE-corrected), the left IPS (F6,84 = 7.53; p = 0.0004, FWE-corrected), and the right IPS (F6,84 = 5.97; p = 0.001, FWE-corrected).
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