The motor component of pain anticipation: corticospinal excitability as a conditioned response

Pain is an adaptive and predictive experience, serving not only as a reaction to injury but also as a mechanism for anticipating and preventing harm. The human brain continuously generates predictions about potential bodily threats, preparing the motor system for defensive responses before nociceptive input occurs. Despite extensive evidence of sensory, affective, and cognitive modulation during pain anticipation, the motor component of this process remains poorly understood. To address this gap, the studies reported in this thesis aim to investigate how predictive learning of painful stimulation engages the motor system. Specifically, we examined how corticospinal excitability encodes the intensity, spatial location, and timing of anticipated acute pain. By combining Pavlovian conditioning with transcranial magnetic stimulation (TMS) and autonomic recordings, results revealed sensory-tuned, topographically organized in both hemispheres, and sustained motor inhibition, characterized by muscle-specific reductions in corticospinal excitability in the upper limbs that reflect the predicted features of pain. This motor modulation occurs alongside global autonomic adjustments, indicating parallel recruiting of complementary systems. Together, these findings highlight how the brain integrates motor and autonomic responses to optimize anticipatory defense, while also revealing mechanisms that may contribute to maladaptive conditions when persistent or altered.