title: Modular organization of the head retraction responses elicited by electrical painful stimulation of the facial skin in humans.
abstract: OBJECTIVE
  To explore whether the trigeminocervical reflexes (TCRs) show a reflex receptive field organization in the brainstem.
  
  
  METHODS
  The facial skin of 16 healthy subjects was electrically stimulated at nine sites reflecting the distribution of the three branches of the trigeminal nerve. The reflex-evoked EMG responses were measured bilaterally from the neck muscles and the head and neck kinematic reactions were detected.
  
  
  RESULTS
  TCRs are site dependent. There was a vertical gradient in the magnitude of the reflex responses. EMG and kinematic reflexes were larger when evoked from ophthalmic and maxillary sites than from mandibular ones. The reflex responses exhibited a crossed right-left behavior. Stimulation of the lateral sites evoked larger reflex responses in the contralateral trapezium muscle as well as head rotation and neck bending away from the stimulated side.
  
  
  CONCLUSIONS
  This modular arrangement of the TCRs seems to be related to withdrawal strategies aimed at protecting the face from injuries, in accordance with the functional role that each group of muscles plays in head and neck motion.
  
  
  CONCLUSIONS
  It is likely that the CNS may exploit the neck muscle synergies revealed by the painful stimulation of the skin face in order to control the head and neck movements.
authors.affiliation: Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 79, 04100 Latina, Italy; Laboratory of Movement Analysis, Policlinico Italia, Piazza del Campidano 6, 00162 Rome, Italy. Electronic address: mariano.serrao@uniroma1.it.
authors.forename: Mariano
authors.initials: M
authors.lastname: Serrao
authors.affiliation: Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 79, 04100 Latina, Italy. Electronic address: francesca.cortese05@libero.it.
authors.forename: Francesca
authors.initials: F
authors.lastname: Cortese
authors.affiliation: Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7-D3, DK-9220 Aalborg, Denmark. Electronic address: oka@hst.aau.dk.
authors.forename: Ole Kæseler
authors.initials: OK
authors.lastname: Andersen
authors.affiliation: Laboratory of Movement Analysis, Policlinico Italia, Piazza del Campidano 6, 00162 Rome, Italy. Electronic address: conte_carmela@libero.it.
authors.forename: Carmela
authors.initials: C
authors.lastname: Conte
authors.affiliation: Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7-D3, DK-9220 Aalborg, Denmark. Electronic address: espaich@hst.aau.dk.
authors.forename: Erika G
authors.initials: EG
authors.lastname: Spaich
authors.affiliation: Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 79, 04100 Latina, Italy. Electronic address: gaia.fragiotta@hotmail.it.
authors.forename: Gaia
authors.initials: G
authors.lastname: Fragiotta
authors.affiliation: INAIL, Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Via Fontana Candida 1, 00040 Monteporzio Catone, Rome, Italy. Electronic address: a.ranavolo@inail.it.
authors.forename: Alberto
authors.initials: A
authors.lastname: Ranavolo
authors.affiliation: G.B. Bietti Foundation IRCCS, Department of Neurophysiology of Vision and Neurophthalmology, Via Livenza 3, 00198 Rome, Italy. Electronic address: gianluca.coppola@gmail.com.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Coppola
authors.affiliation: IRCCS Neuromed, Via Atinense 18, 86077 Pozzilli, Isernia, Italy. Electronic address: armando.perrotta@neuromed.it.
authors.forename: Armando
authors.initials: A
authors.lastname: Perrotta
authors.affiliation: Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 79, 04100 Latina, Italy. Electronic address: fpierelli@gmail.com.
authors.forename: Francesco
authors.initials: F
authors.lastname: Pierelli
mesh_terms: D000328:Adult; D004558:Electric Stimulation / Q000009:adverse effects; D004576:Electromyography / Q000379:methods; D005145:Face / Q000502:physiology*; D005260:Female; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D008297:Male; D009334:Neck Muscles / Q000502:physiology; D010147:Pain Measurement / Q000379:methods*; D012018:Reflex / Q000502:physiology*; D012879:Skin Physiological Phenomena; D014276:Trigeminal Nerve / Q000502:physiology; D055815:Young Adult
keywords: Electromyography; Head retraction reflexes; Kinematics; Modular organization; Reflex receptive field; Trigeminocervical reflexes; Withdrawal reflex