Modification of cortical excitability in neuropathic rats: a voltage-sensitive dye study.
Recent advances in optical imaging techniques have made it possible to monitor neural activity and provided powerful tools to reveal the spatiotemporal patterns of neural activity. We used optical imaging to determine whether nerve injury affects excitability of the sensory cortex. Male Sprague-Dawley rats were subjected to neuropathic surgery consisting of a tight ligation and transection of the left tibial and sural nerves while under pentobarbital anesthesia. The rats were reanesthetized with urethane two weeks post-operatively, and the exposed cortex surfaces were stained with a voltage-sensitive dye (di-2-ANEPEQ). After electrical stimulation of the receptive field, optical signals from the cerebral cortex were recorded using an optical imaging system. Increased optical intensity and an enlarged area of activation were observed in the cerebral cortex of neuropathic rats during electrical stimulation compared to normal or sham-operated rats. Higher electric stimulation resulted in more intensity and a larger area of activation in neuropathic rats. These results suggest that cortical excitability, resulting from peripheral stimulation, may be affected by nerve injury, which indicates a degree of neural plasticity.
Cha
Myeoung Hoon
MH
Department of Physiology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea.
Kim
Dae Shik
DS
Cho
Zang-Hee
ZH
Sohn
Jin-Hun
JH
Chung
Myung-Ae
MA
Lee
Hye-Jung
HJ
Nam
Taick Sang
TS
Lee
Bae Hwan
BH
D000200:Action Potentials; D000818:Animals; D001931:Brain Mapping / Q000379:methods*; D005073:Evoked Potentials, Somatosensory; D005456:Fluorescent Dyes; D008297:Male; D009437:Neuralgia / Q000503:physiopathology*; D009473:Neuronal Plasticity; D051381:Rats; D017207:Rats, Sprague-Dawley; D013003:Somatosensory Cortex / Q000503:physiopathology*; D013497:Sural Nerve / Q000293:injuries* / Q000503:physiopathology*
D005456:Fluorescent Dyes