Activation-related to modulation of attention prior to training (pre-training session).

<p>Subtracting dual-task 80% Equation (80/20) from dual-task 20% Equation (20/80) involves activation in the left superior and medial frontal gyrus (A and B), and left superior temporal and left cingulate gyrus (B). The threshold for display is P<0.001, uncorrected, 10 voxels. Coloured bar is representative of t scores mentioned in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102710#pone-0102710-t005" target="_blank">table 5</a>. “L” denotes the left side of the brain, while “R” denotes the right side.</p

Experimental paradigm.

<p>Schematic representation of the task conditions order in fMRI (A), as well as the alphanumeric equation and visual detection tasks in both single-task (B) and dual-task (C).</p

SINGLE REPEATED training effect.

<p>Decreased (Pre>Post) activation in single-task with alphanumeric equation is found in the right inferior and middle frontal gyrus (A and B) and left middle frontal (B). Histogram in (C) indicates the Beta value (activity estimates ± SE) in right inferior and middle frontal gyrus. The threshold for display is P<0.001, uncorrected, 10 voxels. Coloured bar is representative of t scores mentioned in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102710#pone-0102710-t005" target="_blank">Table 5</a>. “L” denotes the left side of the brain, while “R” denotes the right side.</p

BOLD signal pre and post-intervention for the DIVIDED VARIABLE training.

<p>Beta value (activity estimates ± SE) in pre- and post-training sessions for single-task (visual detection > rest; alphanumeric equation > rest) and for each dual-task condition (80% Equation (80/20) > rest, 50% Equation (50/50) > rest and 20% Equation (20/80) > rest) in Right area 10 - the region showing post-training effect.</p

Mean age, mean education, and mean score on clinical measures (S.D. in parentheses).

<p>Mean age, mean education, and mean score on clinical measures (S.D. in parentheses).</p

Flow chart according to the Consort reporting instructions.

<p>Flow chart according to the Consort reporting instructions.</p

Feedback during variable training.

<p>Four examples of the histograms that provided visual feedback to the participants in the DIVIDED VARIABLE training group. The dark column represents the performance of alphabetical equation that was obtained under single-task baseline. The light column shows performance that was reached in the dual-task condition. The line represents the level of performance that was expected. (a; b) Examples of an 80% Equation trial where participants were asked to allocate 80% of their attention to the alphanumeric equation task: a) shows a trial where performance was below the expected threshold; (b) shows a trial where participants succeeded to obtain the expected level of performance. (c; d) Example of a 50% Equation trial where participants were asked to allocate 50% of their attention to the alphanumeric equation task: c) shows a trial where performance was below the expected threshold; (d) shows a trial where participants succeeded to obtain the expected level of performance.</p

Activations related to dual-tasking prior to training (pre-training session).

<p>Network of prefrontal activation in dual-task, with more emphasis on equation (80% Equation (80/20)) in <b>A</b> and <b>B</b>; equal division of attention (50% Equation (50/50)) in <b>C</b> and <b>D</b>; and more emphasis on detection (20% Equation (20/80)) in <b>E</b> and <b>F.</b> The threshold for display is P<0.001, uncorrected, 10 voxels. Coloured bar is representative of t scores mentioned in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102710#pone-0102710-t005" target="_blank">Table 5</a>. “L” denotes the left side of the brain, while “R” denotes the right side.</p

Brain regions associated with dual-task at pre training by pooling all participants.

<p>P<0.001 uncorrected, K = 10.</p

Brain regions associated with training (Pre

<p>P<0.001 uncorrected, K = 10.</p