title: In vivo voltage-sensitive dye imaging of the insular cortex in nerve-injured rats.
abstract: The insular cortex (IC) is a pain-related brain region that receives various types of sensory input and processes the emotional aspects of pain. The present study was conducted to investigate spatiotemporal patterns related to neuroplastic changes in the IC after nerve injury using voltage-sensitive dye imaging. The tibial and sural nerves of rats were injured under pentobarbital anesthesia. To observe optical signals in the IC, rats were re-anesthetized with urethane 7days after injury, and a craniectomy was performed to allow for optical imaging. Optical signals of the IC were elicited by peripheral electrical stimulation. Neuropathic rats showed a significantly higher optical intensity following 5.0mA electrical stimulation compared to sham-injured rats. A larger area of activation was observed by 1.25 and 2.5mA electrical stimulation compared to sham-injured rats. The activated areas tended to be larger, and the peak amplitudes of optical signals increased with increasing stimulation intensity in both groups. These results suggest that the elevated responsiveness of the IC to peripheral stimulation is related to neuropathic pain, and that neuroplastic changes are likely to be involved in the IC after nerve injury.
authors.affiliation: Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
authors.forename: Jeongsoo
authors.initials: J
authors.lastname: Han
authors.affiliation: Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
authors.forename: Myeounghoon
authors.initials: M
authors.lastname: Cha
authors.affiliation: Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
authors.forename: Minjee
authors.initials: M
authors.lastname: Kwon
authors.affiliation: Division of Bio and Health Sciences, Mokwon University, Daejeon 35349, Republic of Korea.
authors.forename: Seong-Karp
authors.initials: SK
authors.lastname: Hong
authors.affiliation: Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
authors.forename: Sun Joon
authors.initials: SJ
authors.lastname: Bai
authors.affiliation: Department of Physiology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Republic of Korea. Electronic address: bhlee@yuhs.ac.
authors.forename: Bae Hwan
authors.initials: BH
authors.lastname: Lee
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006930:Hyperalgesia / Q000503:physiopathology; D008297:Male; D009437:Neuralgia / Q000503:physiopathology; D009473:Neuronal Plasticity; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000293:injuries*; D056969:Voltage-Sensitive Dye Imaging
keywords: Insular cortex; Nerve injury; Neuropathic pain; Neuroplasticity; Optical imaging; Voltage-sensitive dye