Metacognition and feedback monitoring. rTMS(repeated transcranial magnetic stimulation) applied on dorsolateral prefrontal cortex affects feedback processing

External feedback from contextual cues allows humans to behave appropriately in their environments. Presentation of feedback provides an external indication that allows subjects to modify their behavioural responses upon perceiving a negative signal (feedback of an error) as a consequence of their performance (Balconi & Crivelli, 2010a; 2010b). However, subjects are also required to evaluate the reliability of the information furnished by the external environment. This monitoring mechanism is likely supported by meta-level functions that intervene to compare expected feedback to observed feedback. Indeed, a multi-stage model that governs this monitoring process was proposed; the process produces a coherent representation of the subject’s performance and confronts this performance with external feedback. A particular cognitive system operates to compare the correctness of the observed performance (first-order representation) with the correctness of the feedback information, derived by the external device (second-order representation). How the brain modulates feedback monitoring functions remains unknown. In the present study, the explicit response to veridical vs. false feedback was explored. In addition, the contribution of the prefrontal cortex in this monitoring process was tested by administering an rTMS inhibitory paradigm. Seventeen subjects participated in the study and were required to detect correct vs. incorrect feedback. The experimental task included three main phases: the subject’s performance (spatial decisional task); the system’s response to the performance (external feedback); and the subject’s judgment and response to this external feedback (feedback monitoring). A systematic mismatch was introduced between the expected feedback information and the observed feedback (incorrect feedback), which was linked to the subject’s performance. In other words, a mismatch was prompted between the internal expectation and the unattended external information by manipulating the external response of the computer device. rTMS was performed on the DLPFC. As showed by the behavioural measures, DLPFC deactivation induced worse performance (higher ER and RT) for both correct and incorrect feedback. Indeed, this prefrontal region seems to contribute to conscious monitoring functions. when an explicit response is required. This study revealed the presence of systematic behavioural response modulation based on DLPFC inhibition during external feedback processing, and a causal role of the DLPFC may be suggested for feedback monitoring