Brain studies reveal the mechanisms of the voluntary control of visual...( ants also orient their visual attention...),Health

The fMRI findings -- first reported in January 2004 in the Journal of Cognitive Neuroscience -- showed that lateral parts of the frontal-parietal network were more involved in "cue interpretation," Woldorff said. Meanwhile, regions of the network closer to the brain's midline were more specifically involved in "attentional orienting."

But since fMRI recordings cannot delineate the relative timing of these activations, the researchers launched their current study, which followed the same experimental design used in the earlier study but incorporated time-sensitive ERP recordings.

The study revealed that both the attention-directing cues and the "no-target-will-appear" cues evoked similar electrical activity during the first 300-400 milliseconds following their appearance on the screen. After that, electrical brain activity for the "no-target-will-appear" cues quickly ebbed away, whereas activity for attention-directing cues continued for an extended period.

According to Grent-'t-Jong and Woldorff, these results indicated that the initial electrical response up to 400 milliseconds mainly reflected general cue processing activity. In contrast, the later continuing electrical activity was due primarily to the participants' following the attention-directing cue's instruction to covertly orient attention to the left or right side of the screen.

The prolonged response to the attention-directing cues began initially over only the front part of the scalp, later extending to parietal scalp areas over the top and upper rear of the head. This pattern of ERP activity suggested an initial start of attentional orienting in frontal areas only, followed by joint activity in both frontal and parietal attentional control brain areas, Wol
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Contact: Monte Basgall
monte.basgall@duke.edu
919-681-8057
Duke University
3-Jan-2007