MURAGAKI Yoshihiro    Department   School of Medicine(Tokyo Women's Medical University Hospital), School of Medicine    Position   Visiting Professor
Article types	Original article
Language	English
Peer review	Peer reviewed
Title	Why intra-epidermal electrical stimulation achieves stimulation of small fibres selectively: a simulation study
Journal	Formal name：Physics in Medicine & Biology Abbreviation：Phys Med Biol ISSN code：1361-6560 (Electronic)0031-9155 (Linking)
Volume, Issue, Page	61(12),pp.4479-4490
Author and coauthor	MOTOGI Jun†, SUGIYAMA Yukiya , Ilkka Laakso, HIRATA Akimasa , INUI Koji, TAMURA Manabu, MURAGAKI Yoshihiro
Publication date	2016/05
Summary	The in situ electric field in the peripheral nerve of the skin is investigated to discuss the selective stimulation of nerve fibres. Coaxial planar electrodes with and without intra-epidermal needle tip were considered as electrodes of a stimulator. From electromagnetic analysis, the tip depth of the intra-epidermal electrode should be larger than the thickness of the stratum corneum, the electrical conductivity of which is much lower than the remaining tissue. The effect of different radii of the outer ring electrode on the in situ electric field is marginal. The minimum threshold in situ electric field (rheobase) for free nerve endings is estimated to be 6.3 kV m(-1). The possible volume for electrostimulation, which can be obtained from the in situ electric field distribution, becomes deeper and narrower with increasing needle depth, suggesting that possible stimulation sites may be controlled by changing the needle depth. The injection current amplitude should be adjusted when changing the needle depth because the peak field strength also changes. This study shows that intra-epidermal electrical stimulation can achieve stimulation of small fibres selectively, because Abeta-, Adelta-, and C-fibre terminals are located at different depths in the skin.
DOI	10.1088/0031-9155/61/12/4479
Document No.	27223492