Abstract: PURPOSE: The term cueing effects reflects a behavioral benefit that human use cueing contents to facilitate selection. Compared to numerous functional brain studies, only limited data is available for the neuroanatomical basis of cueing effects. Here we used structural MRI (sMRI) data to investigate whether cueing effects were associated with specific brain structure within frontoparietal attention network.
METHODS: Participants performed visual selective attention task. At the start of each block, they were informed the location of a distractor or target would appear, or there was no spatial information. We applied voxel-based morphometry (VBM) analysis on sMRI data and subsequently separated regions related to distractor and target cueing effects respectively.
RESULTS: Cueing effects on visual search were significant, participants responded faster to the target when the location of the distractor or target was cued. For VBM analysis, we constrained our regions of interest to frontal and parietal lobes. Distractor cueing effects yielded exclusively negative associations with gray matter volume (GMV) in the right middle frontal cortex (rMFG, [29, 47, 26], BA 9) and positive associations in the bilateral superior frontal gyrus (SFG). Only positive correlation between target cueing effects and GMV was found in another subregion of rMFG ([50, 9, 50], BA 6).
CONCLUSIONS: These results reveal that frontal cortex specific morphometric feature accounts for participants' cueing effects, which show more consistent previous functional activations. Two fractionated areas in the rMFG may mediate distinct neural circuits in attention control. A higher processing efficiency in lower GM within anterior rMFG, which is consonant with synapse pruning hypothesis. In contrast, observers with greater GMV in posterior rMFG show more potential to target cues.

Key words: visual attention, cueing effects, sMRI, gray matter