Significant statistical results.

<p>Statistical results on the activity strength in the visual cortex, superior parietal lobe (SPL), inferior parietal lobe (IPL) and middle frontal gyrus (MFG) for selected temporal intervals. The most important statistical findings are reported in bold.</p

MEG results.

<p>A: Mean normalized intensity across all conditions and subjects over time for selected ROIs. Vertical bars indicate the temporal intervals with the highest intensity values established by statistical analysis. Horizontal line indicate the cut-off value (mean+sd). B: Group mean temporal activity was averaged for all conditions for areas showing strongest activity after the matching stimulus. Coloured bars indicate temporal intervals determined previously from statistical analysis and used in the following statistical analyses to compare source activity across conditions (50–150 ms for visual cortex, 50–400 ms for superior parietal lobe, 50–550 ms for inferior parietal lobe and 350–1000 ms for middle frontal gyrus); C: Spatial maps of activations for each areas.</p

Involved areas.

<p>Brodmann areas (BA) and Talairach coordinates in mm of the center of clusters.</p

Behavioural results.

<p>A: Response time for spatial relation, visual field and cue size main effects; B: Accuracy for spatial relation main effect and interaction between spatial relation and cue size. Error bars represent the standard deviations for the main effect and 95% confidence intervals computed with the formula of Loftus and Masson <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083434#pone.0083434-Loftus1" target="_blank">[72]</a> for within-subject designs.</p

Experimental paradigm.

<p>A: Example of an experimental valid trial of the categorically (CAT) different condition with its timing; B: Example of sample stimulus (a) and matching stimulus when it is categorically different (b, CAT), coordinately different (c, COO) and identical (d, NoCh) to the sample stimulus; C: Attention window with large (a) and small cue (b).</p

Significant statistical results.

<p>Statistical results on peak latency in the visual cortex, superior parietal lobe (SPL), inferior parietal lobe (IPL) and middle frontal gyrus (MFG) for selected temporal intervals.</p

Significant statistical results.

<p>Relevant statistical results for the strength (A) and peak latency (B) obtained for the inferior parietal lobe. In the left hemisphere categorical spatial relations yielded greater activity and longer latencies when the attention window was small; in the right hemisphere, coordinate spatial relations yielded greater activity and longer latencies when the attention window was large. Error bars are computed according to the formula for within-subject designs by Loftus and Masson <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083434#pone.0083434-Loftus1" target="_blank">[72]</a> * p<005; **p<0001, significant post hoc comparisons.</p

Experimental paradigm.

<p>The different phases of the experimental paradigm are reported along the time-line. Grey box corresponds to the time of tDCS stimulation, which included the encoding task (A: anodal stimulation; C: cathodal stimulation; S: sham stimulation).</p