A multi-modal investigation of behavioral adjustment: Post-error slowing is associated with white matter characteristics

When people make mistakes in speeded cognitive tasks, their response time on the next trial will typically be slower. This is referred to as post-error slowing (PES), and is important for optimization of performance, but its exact function remains to be decided. However, although PES is relatively stable over time, we have almost no knowledge about how PES is affected by structural brain characteristics. The aim of this study was to test to what extent white matter (WM) macro- and microstructure can account for individual differences in PES. PES was calculated for 255 healthy participants who performed a modified version of the Eriksen flanker task and underwent structural magnetic resonance imaging and diffusion tensor imaging (DTI). PES was positively related to WM volume in the caudal and rostral middle and superior frontal, medial orbitofrontal gyri and pars orbitalis. DTI analyses with tract-based spatial statistics (TBSS) showed that mean diffusivity in the superior longitudinal fasciculus, inferior fronto-occipital fasciculus and anterior thalamic radiation, as well as axial diffusivity in the corpus callosum, was negatively related to PES. Path analysis demonstrated that WM micro- and macrostructure were complementary in accounting for PES. It is concluded that individual differences in WM characteristics can partly explain why some people are better at adjusting their behavior in response to poor performance than others.