Kinematic and electromyographic study of the nociceptive withdrawal reflex in the upper limbs during rest and movement

Mariano Serrao, Francesco Pierelli, Romildo Don, Alberto Ranavolo, Angelo Cacchio, Antonio Currà, Giorgio Sandrini, Massimo Frascarelli, Valter Santilli

Research output: Contribution to journalArticlepeer-review


This study set out to evaluate nociceptive withdrawal reflex (NWR) excitability and the corresponding mechanical response in the upper limbs during rest and movement.Weused a three-dimensional motion analysis system and a surface EMG system to record, in 10 healthy subjects, the NWR in eight upper limb muscles and the corresponding mechanical response in two experimental conditions: rest and movement (reaching for, picking up, and moving a cylinder). The NWR was elicited through stimulation of the index finger with trains of pulses delivered at multiples of the pain threshold (PT). We correlated movement types (reach-to-grasp, grasp-and-lift), movement phases (acceleration, deceleration), and muscle activity types (shortening, lengthening, isometric) with the presence/absence of the NWR (reflex-muscle pattern), with NWR size values, and with the mechanical responses. At rest, when the stimulus was delivered at 4X PT, the NWR was present, in all muscles, in >90%of trials, and the mechanical response consisted of wrist adduction, elbow flexion, and shoulder anteflexion. At this stimulus intensity, during movement, the reflex-muscle pattern, reflex size, and mechanical responses were closely modulated by movement type and phase and by muscle activity type. We did not find, during movement, significant correlations with the level of EMG background activity. Our findings suggest that a complex functional adaptation of the spinal cord plays a role in modulating the NWR in the transition from rest to movement and during voluntary arm movement freely performed in three-dimensional space. Study of the upper limb NWR may provide a window onto the spinal neural control mechanisms operating during movement.

Original languageEnglish
Pages (from-to)3505-3513
Number of pages9
JournalJournal of Neuroscience
Issue number13
Publication statusPublished - Mar 29 2006


  • Central pattern generator
  • Movement analysis
  • Movement phase
  • Nociceptive withdrawal reflex
  • Painful stimulation
  • Spinal interneurons
  • Spinal reflexes
  • State dependent

ASJC Scopus subject areas

  • Neuroscience(all)


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