Regression analyses on successful and erroneous trials.

<p>Brain regions showing significant positive and negative correlations across the total sample (N = 24) on successful and erroneous perceptual conflict trials (p<.005 uncorr., k>70 voxels).</p

Distribution of brain activation across successful and error trials during perceptual conflict.

<p>Random effects analyses of perceptual conflict trials (p<.005 uncorr., k>70 voxels) showed different activation patterns across the total sample and performance groups. (<b>A</b>) On successful trials across the total sample (upper panel) an activation pattern emerged encompassing PHG (BA's 35, 36) and caudate body. Good performers (lower left panel; shown in green) exhibited a more widely distributed activation pattern including fronto-limbic (BA's 11, 25), temporal (BA's 19, 39) and more posterior regions in the posterior cingulate (BA 30) and PHG (BA's 28, 35). Poor performers (lower right panel; shown in red) revealed no significant activation. (<b>B</b>) On error trials the total sample (upper panel) showed activation in fronto-parietal regions encompassing BA's 6, 9, 11, 32, 46 and 40. While for good performers (lower left panel; shown in green) no significant activation was seen poor performers (lower right panel; shown in red) revealed activation clusters in IFG and MFG (BA's 46, 47).</p

Behavioral data.

<p>Response times and error rates across all trial types for both the total sample and performance groups.</p

Differential neuronal responses of performance during perceptual conflict.

<p>Regions of activation associated with the perceptual conflict condition between good and poor performers (p<.005 uncorr., k>70 voxels) and corresponding beta estimates. Using ANOVAs activation clusters elicited by good performers were seen in the RG (BA 11), ACC (BA 25), IPL (BA 40) and visual areas V2 and V3. Poor performers robustly activated only the IPL (BA 39). Corresponding beta estimates revealed significant differences between good and poor performers in any of these regions.</p

Activation patterns in good and poor performers on perceptual conflict trials.

<p>Brain regions significantly activated across good (N = 8) and poor performers (N = 8) on perceptual conflict trials as derived from the ANOVA (p<.005 uncorr., k>70 voxels).</p

Random effects analyses on error trials.

<p>Brain regions showing significant activations across the total sample (N = 24) and good performers (N = 8) on erroneous perceptual conflict trials (p<.005 uncorr., k>70 voxels). No activation clusters were evident in good performers (N = 8).</p

Regression analyses during perceptual conflict trials.

<p>(<b>A</b>) On successful perceptual conflict trials regression analyses revealed a significant positive correlation between task performance and brain activations in IFG (BA 9) and ANG (BA 39) (upper panel). A negative correlation (lower panel) was evident in ACC (BA 33), CG (BA's 24, 32), middle (BA 21) and superior temporal gyrus (BA 22), PHG (BA 19), MOG (BA 19) and caudate tail. (<b>B</b>) Activation clusters derived from the regression analyses across successful trials revealed significant differences in beta estimates between good and poor performance only in the ANG (BA 39) by means of an independent samples t-test. (<b>C</b>) However, regression analyses showed significant positive and negative correlations in the left ANG (BA 39), bilateral ACC (BA 33), left CG (BA 24) and right MTG (BA 21). Scatter plots show regional mean beta estimates for each subject plotted against their performance scores. (<b>D</b>) On error trials task performance led to a robust positively correlated activation in the PHG (BA 28) (upper panel). The negatively correlated performance-brain relationship indicated activations in the medial (BA 6) and superior frontal gyrus (BA 8), STG (BA 39) and BA 40 encompassing the IPL and ANG (lower panel). (<b>E</b>) Activation clusters derived from the regression analyses across error trials revealed no significant differences in beta estimates between good and poor performance. (<b>F</b>) As indicated by regression analyses a negative correlation yielded significance in the PHG (BA 28) and a significant positive correlation in the MeFG (BA 6). Scatter plots show regional mean beta estimates for each subject plotted against their performance score.</p

Stimuli set-up and experimental procedure.

<p>Within-subject factor type of stimulus change comprises luminance change of one bar (LUM), orientation change of one bar (ORI), luminance and orientation change of one bar (Luminance Orientation Unilateral = LOU) and luminance and orientation change across two bars (Luminance Orientation Bilateral = LOB). Participants were instructed to detect a change in luminance in a sequence of two frames.</p

Behavioral results.

<p>Mean response times (<b>A</b>) and error rates (<b>B</b>) for the total sample (N = 24; shown in blue), good performers (N = 8; shown in green) and poor performers (N = 8; shown in red); error bars depict standard error. Both response times and error rates were highest on perceptual conflict trials (LOB) in comparison to non-conflict trials (LUM, ORI, LOU). Missing reaction times for the ORI condition indicate no-go trials subjects were instructed not to respond to.</p