Clinical evidence suggests that head movements may be coupled with oro-facial functions, which are predominantly controlled by somatosensory inputs from the oro-facial area. However, the effects of specific modalities of sensory inputs on the neck muscles’ motor activity are still unclear. In the present study, natural pressure stimulation was applied to the rat's upper first molars, while motor unit electromyographic activity was recorded from the dorsal neck splenius muscle. During the hold phase of pressure stimulation, clear tonic discharges were elicited in the splenius muscles on both sides. Mean threshold values were 622.3 mN (± 19.6 SEM, n = 39) and 496.8 mN (± 26.4 SEM, n = 43) for ipsi- and contralateral sides, respectively (p < 0.001, Mann-Whitney U test). Analysis of our data suggests that periodontal inputs may play an important role in controlling the motor activity of neck muscles, in addition to its well-known coordination of the masticatory function.
AbrahamsV.C., RichmondF.J. (1977). Motor role of the spinal projections of the trigeminal system. In: Pain in the trigeminal region.AndersonD.J., MatthewsB., editors. Amsterdam: Elsevier/North Holland, pp. 405–411.
2.
AbrahamsV.C., KoriA.A., LoebG.E., RichmondF.J., RoseP.K., KeirsteadS.A. (1993). Facial input to neck motoneurons: trigemino-cervical reflexes in the conscious and anaesthetised cat.Exp Brain Res97: 23–30.
3.
AlstermarkB., PinterM.J., SasakiS., TantisiraB. (1992). Trigeminal excitation of dorsal neck motoneurones in the cat.Exp Brain Res92: 183–193.
4.
ChangC.M., KubotaK., LeeM.S., IsekiH., SonodaY., NaritaN.. (1988). Degeneration of the primary snout sensory afferents in the cervical spinal cords following the infraorbital nerve transection in some mammals.Anat Anz166(1-5): 43–51.
5.
DarlingD.W., KrausS., Glasheen-WrayM.B. (1984). Relationship of head posture and the rest position of the mandible.J Prosthet Dent52: 111–115.
6.
EmshoffR., BertramS. (1998). The short-term effect of stabilization-type splints on local cross- sectional dimensions of muscles of the head and neck.J Prosthet Dent80: 457–461.
7.
ErikssonP.O., Haggman-HenriksonB., NordhE., ZafarH. (2000). Coordinated mandibular and head-neck movements during rhythmic jaw activities in man.J Dent Res79: 1378–1384.
8.
FerrarioV.F., SforzaC., PoggioC.E., SchmitzJ.H., TartagliaG. (1997). A three-dimensional non-invasive study of head flexion and extension in young non-patient subjects.J Oral Rehabil24: 361–368.
9.
GoldsteinD.F., KrausS.L., WilliamsW.B., Glasheen-WrayM. (1984). Influence of cervical posture on mandibular movement.J Prosthet Dent52: 421–426.
10.
HellsingE., HagbergC. (1990). Changes in maximum bite force related to extension of the head.Eur J Orthod12: 148–153.
11.
IgarashiN., YamamuraK., YamadaY., KohnoS. (2000). Head movements and neck muscle activities associated with the jaw movement during mastication in the rabbit.Brain Res871: 151–155.
12.
JacobsR., van SteenbergheD. (1994). Role of periodontal ligament receptors in the tactile function of teeth: a review.J Periodontal Res29: 153–167.
13.
KarppinenK., EklundS., SuoninenE., EskelinM., KirveskariP. (1999). Adjustment of dental occlusion in treatment of chronic cervicobrachial pain and headache.J Oral Rehabil26: 715–721.
14.
KerrF.W. (1972). Central relationships of trigeminal and cervical primary afferents in the spinal cord and medulla.Brain Res43: 561–572.
15.
MatsushitaM., OkadoN., IkedaM., HosoyaY. (1981). Descending projections from the spinal and mesencephalic nuclei of the trigeminal nerve to the spinal cord in the cat. A study with the horseradish peroxidase technique.J Comp Neurol196: 173–187.
16.
McKayD.C., ChristensenL.V. (1999). Electrognathographic and electromyographic observations on jaw depression during neck extension.J Oral Rehabil26: 865–876.
17.
PfisterJ., ZenkerW. (1984). The splenius capitis muscle of the rat, architecture and histochemistry, afferent and efferent innervation as compared with that of the quadriceps muscle.Anat Embryol169: 79–89.
18.
PhelanK.D., FallsW.M. (1991a). The spinotrigeminal pathway and its spatial relationship to the origin of trigeminospinal projections in the rat.Neuroscience40: 477–496.
19.
PhelanK.D., FallsW.M. (1991b). A comparison of the distribution and morphology of thalamic, cerebellar and spinal projection neurons in rat trigeminal nucleus interpolaris.Neuroscience40: 497–511.
20.
RobinsM.W. (1977). Biting loads generated by the laboratory rat.Arch Oral Biol22: 43–47.
21.
RuggieroD.A., RossC.A., ReisD.J. (1981). Projections from the spinal trigeminal nucleus to the entire length of the spinal cord in the rat.Brain Res225: 225–233.
22.
SatoT., IidaJ., KuriharaS. (1984). A histological study of the periodontal tissue changes during molar depression in rats.Nippon Kyosei Shika Gakkai Zasshi43: 361–372 (in Japanese).
23.
SuminoR., NozakiS. (1977). Trigemino-neck reflex: its peripheral and central organization. In: Pain in the trigeminal region.AndersonD.J., MatthewsB., editors. Amsterdam: Elsevier/North Holland, pp. 365–374.
24.
TrulssonM., GunneH.S. (1998). Food-holding and -biting behavior in human subjects lacking periodontal receptors.J Dent Res77: 574–582.
25.
TrulssonM., JohanssonR.S. (1996). Encoding of tooth loads by human periodontal afferents and their role in jaw motor control.Prog Neurobiol49: 267–284.
26.
VeyruneJ.L., MiocheL. (2000). Complete denture wearers: electromyography of mastication and texture perception whilst eating meat.Eur J Oral Sci108: 83–92.
