Neural correlates of feedback processing during a sensory uncertain speech - nonspeech discrimination task

Abstract

Performance feedback during a speech-nonspeech discrimination task was used to investigate (neuro-)cognitive processes underlying feedback processing under uncertainty. Sensory uncertainty was manipulated by creating stimuli that were stepwise morphs of the German vowels /a/ and /a:/ (speech) and their spectrally rotated counterparts (non-speech). The anterior N1 associated with early attentional modulation was largest following negative feedback. Both negative and uninformative feedback showed larger FRN amplitudes, suggesting a classification as worse than expected. Sensory uncertainty affected only the feedback-P3, in terms of larger amplitudes for (1) stimuli with high uncertainty and (2) positive feedback. Confidence ratings revealed that sensory uncertainty reduced the accuracy of stimulus categorization, but did not modulate participants’ response confidence. Results suggest that feedback processing follows three distinct and successive stages, starting with initial screening for behavioral relevance (anterior N1, enhanced for unexpected negative feedback), followed by a binary valence distinction (FRN), and a more detailed analysis (P3).