Speed-accuracy trade-offs during the antisaccade task.

<p>A: A schematic depiction of the speed-accuracy trade-off (SATO). As reaction time (RT) increases, the probability of an error decreases. The circle denotes the point where optimal accuracy is achieved with the fastest RT. Beyond this point, making faster responses entails a cost in reduced accuracy. B: The antisaccade paradigm. Schematic and timeline of the three conditions: easy, hard, and fake-hard. Each trial lasted four seconds and began with an instructional cue (300 ms), either a blue or yellow ‘X’ that indicated whether the trial was hard or easy. The mapping of cue color to trial type was counterbalanced across participants. The cue was horizontally flanked by two white squares of 0.4° width that marked the potential locations of stimulus appearance, 10° left and right of center. The squares remained visible for the duration of each run. At 300 ms, the instructional cue was replaced by a white fixation ring of 1.3° diameter at the center of the screen. At 1800 ms, the fixation ring disappeared (200 ms gap). At 2000 ms, the fixation ring reappeared at one of the two stimulus locations, right or left with equal probability. This was the imperative stimulus to which the participant responded by making a saccade in the opposite direction. The ring remained in the peripheral location for 1000 ms and then returned to the center, where participants were instructed to return their gaze for 1000 ms before the start of the next trial. Hard trials were distinguished by a 3 db increase in luminance of the peripheral squares starting during the gap. Except for the hard cue, fake-hard trials were identical to easy trials. Fixation epochs were simply a continuation of the fixation display that constitutes the final second of the previous saccadic trial. C: Mean saccadic RT as a function of trial position in relation to an error (ERR) with standard error bars.</p

fMRI activation and its relation to RT and to our theoretical prediction weightings.

<p>Maxima and locations of significant clusters within the default network and dorsal attention network. Clusterwise probabilities (CWP) are based on Monte Carlo correction for multiple comparisons within the default network and dorsal attention network ROIs. Local maxima (indented) are listed for clusters spanning both hemispheres.</p

Statistical maps of the relations of task-based activation with RT (left side) and with integer weightings representing idealized predictions for SATO-based changes in RT and network activation (right side) across trial position, displayed on the MNI152 template brain.

<p>Crosshairs denote the maximum voxel in the cluster of interest. Red indicates a positive correlation and blue indicates an inverse correlation. A, B: rACC and PCC regions of the default network showed an inverse correlation with RT. Graphs plot activation at the maximum voxel (black) and mean RT (green) by trial position with standard error bars. C: The right IPS region of the dorsal attention network showed a positive correlation with RT. D-F: rACC (D) and PCC (E) regions of the default network showed an inverse correlation with prediction weightings while the right IPS region of the dorsal attention network showed a positive correlation (F). Graphs plot activation at the maximum voxel (black) and prediction weightings (red) across trial position.</p

Relations of network coordination, post-error slowing, and the microstructural integrity of the posterior cingulum bundle.

<p>A: The ‘index of network coordination’ quantifies the magnitude of the reciprocal change in default relative to dorsal attention network activation from trial position 1PRE to 1POST. Dashed lines show integer weightings representing predictions for network activation across trial position, red for the dorsal attention network (DAN) and blue for the default network (DN). Open symbols (circles and x’s) are expected activation values at trials 1PRE and 1POST. Filled symbols represent means of activation with standard errors at these positions. For display purposes only, activation values were normalized based on the mean activation across all five trial positions. B: Correlation of network coordination (COORD_DN/DAN), and post-error slowing. C: Same correlation as B, but with the definition of COORD_DN/DAN restricted to network regions in which activation correlated with RT (see Fig. 2A–C). D: Statistical maps of correlations of FA with COORD_DN/DAN displayed on the MNI152 template brain. The posterior cingulum bundle ROI is highlighted in white. Warm and cool colors indicate positive and negative correlations, respectively. Crosshairs in the left and middle images show coronal and sagittal views of the voxel of maximal significance (MNI coordinates: 10, −48, 16). The right image shows that the region of correlation extends along the cingulum bundle to its termination in the parahippocampal gyrus. E: Plot of mean RT across trial position with standard error bars (left) indicating the measurement of post-error slowing (PES). PES was defined as the difference in RT between 1POST and 1PRE. Statistical maps of correlations of FA with post-error slowing (right; peak MNI coordinates: −2, −40, 20).</p

Network measures between SZ at high load and HC at medium load.

<p>Green dots above indicate significant group difference (<i>p</i><0.05, FDR corrected) and pink dots above indicate marginally group difference (<i>p</i><0.1, FDR corrected) between HC and SZ at that observation.</p

The spatial mask applied to build network.

<p>The spatial mask applied to build network.</p

The 3 selected components and their averaged time courses from Group ICA.

<p>The 3 selected components and their averaged time courses from Group ICA.</p

Demographics of Subjects and Symptom Scores for SZ.

<p>Demographics of Subjects and Symptom Scores for SZ.</p

Scatter Plots of averaged clustering coefficients and local efficiency against RT at medium load.

<p>Scatter plots with trend lines showing averaged <i>C_net</i> and <i>E_local,net</i> as function of reaction time in all subjects and each group. Significant negative correlation (<i>p</i><0.05) was found between reaction time and averaged <i>C_net</i> and <i>E_local,net</i> for all subjects (green line).</p

Group comparison on network measures at medium load.

<p>Network measures on individual observations as a function of degree between groups on WM load level 3. Green dots above indicate significant group difference (<i>p</i><0.05, FDR corrected) and pink dots above indicate marginally group difference (<i>p</i><0.1, FDR corrected) between HC and SZ at that observation.</p