Response monitoring without sensory feedback

Objective: The elicitation of an evoked potential, the 'error negativity' (Ne) when subjects commit errors in speeded tasks, is often taken as an index of response monitoring processes. The presence of a Ne-like wave on purely correct trials challenges the current conceptions about the nature of such a monitoring system. Here, we evaluate the possibility that the Ne-like wave on correct trials is merely due to reafferences, and at the same time, we test directly the general opinion according to which the Ne is generated by an internal signal. Methods: We studied the presence of a Ne-like wave in a completely deafferented patient. The patient performed two reaction time (RT) tasks: a two-responses RT task and a go/no-go task. Results: In this patient, a Ne occurs on errors, on incorrect EMG activations, and on purely correct responses. On errors, the Ne was clearly followed by an error positivity (Pe). Conclusions: The Ne and the Ne-like wave are not generated by reafferences. This similarity is a further argument to consider that these two waves are of same nature. Significance: The present data demonstrate that sensory information is not mandatory for the brain to monitor and correct ongoing responses. (C) 2004 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.