Integrating brain function and structure in the study of the human attentional networks

Attention is a heterogeneous function theoretically divided into alerting, orienting, and executive attention. While functional magnetic resonance imaging (fMRI) has extensively characterized their functioning, the role of white matter in cognitive function has gained recent interest due to diffusion-weighted imaging advancements. However, most evidence relies on correlations between white matter properties and behavioral or cognitive measures. This study used a new method that combines the signal from distant voxels of fMRI images using the probability of structural connection given by a high-resolution normative tractography. We analyzed three fMRI datasets with a visual perceptual task and three attentional manipulations (phasic alerting, spatial orienting, and executive attention). The phasic alerting network engaged temporal areas and their communication with frontal and parietal regions, with a left hemisphere dominance. The orienting network involved bilateral fronto-parietal and midline regions communicating by association tracts and interhemispheric fibers. The executive attention network engaged a broad set of brain regions and white matter tracts connecting them, with a particular involvement of frontal areas and their connections with the rest of the brain. These results confirm and extend previous knowledge on the neural substrates of the attentional system, offering a more comprehensive understanding by integrating structure, function, and behavior.

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