Correct and erroneous picture naming responses in healthy subjects.

In this functional magnetic resonance imaging study, brain activations of correct and erroneous picture naming responses were investigated in 34 healthy subjects using an event-related design. We regarded main effects comprising all (ALL), false (FAL), or correct (COR) responses only. Despite the rare error occurrence, activation maxima differed between all three main effects. To investigate the influence of naming accuracy on brain activations, we therefore (1) considered the number of errors as covariates, and (2) compared carefully matched sets of FAL and COR for subjects with higher error rates. As a result, activations in left middle/medial frontal gyrus were significantly correlated with number of errors. The neural substrate of naming errors appears to be separated in several subsystems of activation: first bilateral activations in anterior cingulate cortex (ACC), prefrontal, and premotor regions associated with monitoring processes; second the involvement of right (para)hippocampal gyrus most likely indicating post-error processes of retention; third perisylvian (especially inferior frontal) language areas. These activations were not restricted to false responses, but were with less intensity also recruited for correct responses. In contrast, there was no specific activation for successful name retrieval in correct trials. To conclude, the underlying processing mechanisms of erroneous and correct naming responses are strikingly similar; self-monitoring appears to be a general mechanism of the naming process.