The neural signature of an erroneous thought

The human brain detects errors in overt behavior fast and efficiently. However, little is known about how errors are monitored that emerge on a mental level. We investigate whether neural correlates of error monitoring can be found during inner speech and whether the involved neural processes differ between these non-motor responses and behavioral motor responses. Therefore, electroencephalographic data were collected while participants performed two versions of a decision task that only differed between these response modalities. Erroneous responses were identified based on participants' metacognitive judgments. Correlates of error monitoring in event-related potentials were analyzed by applying residue iteration decomposition on stimulus-locked activity. Non-motor responses elicited the same cascade of early error-related negativity and late error positivity as motor responses. An analysis of oscillatory brain activity showed a similar theta response for both error types. A multivariate pattern classifier trained on theta from the motor condition could decode theta from the non-motor condition, demonstrating the similarity of both neural responses. These results show that errors in inner speech are monitored and detected utilizing the same neural processes as behavioral errors, suggesting that goal-directed cognition and behavior are supported by a generic error-monitoring system.