Musicianship and active musical engagement predict facilitation of auditory-motor plasticity: evidence from auditory-motor paired associative stimulation

Abstract

Background and AimAuditory-motor paired associative stimulation (PAS) probes experience-dependent plasticity in auditory-motor circuits. We tested whether musical experience and musical sophistication modulate PAS-induced facilitation when instrument tones are paired with transcranial magnetic stimulation (TMS) over the left primary motor cortex. MethodSixteen musicians and thirteen non-musicians completed two sessions. Session 1 estimated an individualized inter-stimulus interval (ISI) by testing seven tone-TMS delays (25-300 ms). Session 2 applied PAS at the optimal ISI. Corticospinal excitability was assessed by motor-evoked potentials (MEPs) from right first dorsal interosseus at baseline and post-intervention. Group comparisons and a stepwise multiple regression with Goldsmiths Musical Sophistication Index (Gold-MSI) subscales evaluated predictors of the PAS effect. ResultsA stepwise multiple regression model selected "Group" and "Active Engagement" (Gold-MSI Factor 1) as independent predictors (F (2,26) = 4.59, p = 0.020, adjusted R2 = 0.204), without interaction: musicians exhibited smaller facilitation than non-musicians, and higher Active Engagement predicted greater facilitation across groups. DiscussionThe lack of facilitation in musicians contrasts with somatosensory PAS reports of enhanced plasticity in experts. A modality-specific ceiling effect may contribute, whereby long-term training optimizes auditory-motor transmission, reducing headroom for facilitation. The association with Active Engagement suggests motivational/reward mechanisms--potentially dopaminergic-- gate responsiveness to auditory-motor PAS. ConclusionUnder this protocol, auditory-motor PAS with instrument tones facilitated corticospinal excitability in non-musicians but not in musicians. Individual differences in Active Engagement predicted facilitation, indicating that both group membership and active musical engagement shape susceptibility to auditory-motor associative plasticity.