Long latency response of the mentalis muscle following transcranial magnetic stimulation with a circular coil in normal subjects

Citation
M. Ishikawa et al., Long latency response of the mentalis muscle following transcranial magnetic stimulation with a circular coil in normal subjects, NEUROL RES, 22(5), 2000, pp. 501-504
Citations number
18
Categorie Soggetti
Neurosciences & Behavoir
Journal title
NEUROLOGICAL RESEARCH
ISSN journal
01616412 → ACNP
Volume
22
Issue
5
Year of publication
2000
Pages
501 - 504
Database
ISI
SICI code
0161-6412(200007)22:5<501:LLROTM>2.0.ZU;2-2
Abstract
Short latency response (SLR), middle latency response and long latency resp onse (LLR) are elicited in facial muscles by transcranial magnetic stimulat ion. Although it has been said that the LLRs are elicited by the trigeminal nerve stimulation, a trigeminofacial reflex is recorded easily in normal s ubjects by the electrical stimulation in orbicularis oculi muscles as a bli nd reflex, but a trigeminal-facial reflex recorded in orbicularis oris, nam ely a snout reflex, is more difficult to record in normal subjects. The aim of this study is to demonstrate the LLR of lower facial muscles (mentalis muscle) by the transcranial magnetic stimulation, using a circular coil. Th e transcranial magnetic stimulations were performed over parieto-occipital scalp with frequencies of random and 0.3 Hz in I I normal subjects and the responses in the mentalis muscle were recorded. The LLR of the mentalis mus cle was recorded in all 11 subjects following SLRs. The latency, duration a nd LLR/SLR ratio were 37.4 msec, 20.3 msec and 9.1%, respectively. The wave form of the LLR varied trial to trial showing habituation with a stimulatio n of 0.3 Hz. At this time the LLR of the masseter muscle was not recorded f ollowing this transmagnetic stimulation. It was suggested that the LLR of t he mentalis muscle is recorded by the transcranial magnetic stimulation of the trigeminal nerve with a circular coil. The ease and reliability of thei r recording make it possible to apply this LLR clinically as well as a blin k reflex.