Dissociable Processes of Cognitive Control during Error and Non-Error Conflicts: A Study of the Stop Signal Task

Conflict detection and subsequent behavioral adjustment are critical to daily life, and how this process is controlled has been increasingly of interest. A medial cortical region which includes the anterior cingulate cortex (ACC) has been theorized to act as a conflict detector that can direct prefrontal activity for behavioral adjustments. This conflict monitoring hypothesis was supported by many imaging studies of the Stroop task, with a focus on non-error processes. Here we sought to examine whether this circuit could be generalized to the stop signal task (SST), another behavioral paradigm widely used to study cognitive control. In particular, with a procedure to elicit errors in the SST, we examined whether error and non-error control were mediated by the same pathways.In functional magnetic resonance imaging of 60 healthy adults, we demonstrated that the medial cortical activity during stop success (SS) as compared to go success (G) trials is correlated with increased prefrontal activity in post-stop SS as compared to post-go SS trials, though this correlation was not specific to the medial cortical region. Furthermore, thalamic and insular rather than medial cortical activation during stop error (SE) as compared to G trials correlated with increased prefrontal activity in post-stop SS as compared to post-go SS trials.Taken together, these new findings challenge a specific role of the ACC and support distinct pathways for error and non-error conflict processing in cognitive control

Trial structure of the stop signal and Stroop task.

<p>Example of a trial sequence in stop signal task (b) that parallels that in the Stroop task (a). In the Stroop task, color words that are printed in a color different from what the word says represent incongruent (I) trials; otherwise, they are congruent (C) trials. In the stop signal task, both stop success (SS) and stop error (SE) trials are incongruent trials, and involved in conflict processing, as compared to go (G) trials, which are congruent trials. In both tasks, trials are distinguished by their preceding trials. Thus, an incongruent trial following a congruent trial is “cI” in the Stroop task, and a SS trial following a go trial is “pG-SS” in the stop signal task.</p

Brain regions more activated in stop as compared with go trials.

<p>Statistical threshold: <i>p<0.005</i>, <i>uncorrected</i>; <i>extent</i>, <i>5 voxels</i>. <i>G</i>, <i>Gyrus</i>; <i>S</i>, <i>Sulcus</i>; <i>L</i>, <i>left</i>; <i>R</i>, <i>right</i>; <i>SMA</i>, <i>supplementary motor area</i>. All peak activations greater than 8 mm apart are identified.</p

Brain regions showing more activation in stop as compared with go trials.

<p>BOLD contrasts are superimposed on a T1 structural image in axial sections from <i>z</i> = −25 to <i>z</i> = 65. The adjacent sections are 5 mm apart. The color bar represents voxel T value. L, Left; R, Right.</p

Mediation analysis results between the conflict areas: right visual (R Vis), left insula (L Insul), and left inferior parietal cortex (L IPC), and the post-conflict region right lateral prefrontal cortex (R LPFC) with the potential mediator ACC/SMA.

<p><i>β</i> denotes the regression coefficients and p-values are uncorrected.</p><p>*indicates significant connections at p<0.0125, Bonferroni corrected.</p

Brain regions showing more activation in post- stop as compared with post-go stop success trials.

<p>BOLD contrasts are superimposed on a T1 structural image in axial sections from <i>z</i> = −40 to <i>z</i> = 64. The adjacent sections are 8 mm apart. The color bar represents voxel T value. L, Left; R, Right.</p

Brain regions more activated in post-stop as compared with post-go stop success trials.

<p>Statistical threshold: <i>p<0.005</i>, <i>uncorrected</i>; <i>extent</i>, <i>5 voxels</i>. <i>G</i>, <i>Gyrus</i>; <i>S</i>, <i>Sulcus</i>; <i>L</i>, <i>left</i>; <i>R</i>, <i>right</i>. All peak activations greater than 8 mm apart are identified.</p

R-values of correlations between post-stop as compared with post-go stop success regions and stop success (a) or stop error (b) as compared with go trials.

∧<p>p<0.005.</p>#<p>p<0.001.</p>*<p>p<0.0001.</p><p><i>Thal, Thalamus; Cing, Cingulate; Caud, Caudate; Vis, Visual; Insul, Insula; FPC, Frontopolar Cortex; Occ, Occipital; OFC, Orbitofrontal Cortex; CBL, Cerebellum; IFC, Inferior Frontal Cortex; PPC, Posterior Parietal Cortex; IPC, Inferior Parietal Cortex; L, left; R, right.</i></p