title: c-Fos Expression After Chronic Electrical Stimulation of Sensorimotor Cortex in Rats.
abstract: Objectives.  Motor cortex stimulation has been used as a treatment for intractable pain. However, the mechanisms underlying its effects remain unclear. In this study, neuroplasticity induced by chronic sensorimotor cortex stimulation was investigated experimentally on the basis of c-Fos expression. Materials and Methods.  The experimental animals employed were adult male Wistar rats. A quadripolar stimulation electrode was positioned over the sensorimotor cortex. We examined the neural activation in response to chronic stimulation using c-Fos immunopositivity. Results.  The results are as follows: 1) c-Fos was significantly expressed immediately after the stimulation compared with that in the control; 2) c-Fos expression became extensive over the various regions with an increase in stimulation duration; and 3) after two months of stimulation, c-Fos was expressed not only on the stimulation side, but also within the contralateral cerebral hemisphere. Conclusions.  Changes in c-Fos expression induced by long-term stimulation indicate the existence of a time-dependent neural plasticity.
authors.affiliation: Department of Neurological Surgery, Nihon University School of Medicine and Division of Applied System Neuroscience, Graduate School of Medical Science, Tokyo, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Shijo
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Katayama
authors.forename: Akiko
authors.initials: A
authors.lastname: Yamashita
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Hideki
authors.initials: H
authors.lastname: Oshima
authors.forename: Chikashi
authors.initials: C
authors.lastname: Fukaya
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Yamamoto