Pain Enhances the Auditory P2 but Attenuates Mismatch Response and P3a

Auditory input is known to modulate the perception of pain, yet the reciprocal influence, how pain affects auditory processing, remains less well understood. We investigated how continuous tonic pain dynamically alters auditory cortical responses in humans.

Using a three-stimulus auditory oddball paradigm combined with EEG, we recorded event-related potentials (ERPs) while participants experienced thermal stimulation under three conditions: baseline, non-painful warmth, and pain. We examined multiple stages of auditory processing, including early sensory encoding (N1, P2), automatic deviance detection (MMN), and attentional reorienting (P3a).

Tonic pain modulated auditory ERPs in a stage- and component-specific manner. Compared to baseline and warm conditions, pain was associated with enhanced P2 responses to distractors and reduced MMN and P3a amplitudes, although no statistically significant differences in behavioural performance were observed. This pattern suggests enhanced early salience detection alongside reduced pre-attentive deviance detection and involuntary attentional shifts under pain. The warm condition selectively modulated N1 amplitude, indicating that some effects may be related to the affective and attentional demands of pain rather than somatosensory stimulation per se.

Continuous tonic pain is associated with selective modulation of auditory processing, characterized by enhanced early sensory responsiveness and reduced higher-order attentional engagement. This biphasic neural pattern, observed in the absence of measurable behavioural differences, is consistent with predictive coding and salience network accounts of pain-attention interactions and highlights the sensitivity of ERPs for detecting pain-related neural reweighting. The absence of statistically significant behavioural effects should be interpreted with caution and may reflect relatively subtle or context-dependent influences of pain under the present task conditions.

This study is among the first to systematically examine how experimentally induced tonic pain modulates distinct stages of auditory processing in healthy individuals using high-resolution ERPs, with a task design and hypothesis framework capable of teasing apart the cognitive mechanisms underlying these changes.