Analysis of cortical noxious responses caused by CO2 laser stimulation in the tail of the rat and Development of a mechanical noxious stimulator

• Main Authors: Wen-Li Liao, 廖文琍
• Other Authors: Fu-San Jaw
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/98637750166713010345

碩士 === 國立臺灣大學 === 醫學工程學研究所 === 92 === To probe into the mystery of human brain, we are motivated to study the somatosensory system. Among various sensory modalities, the pain sensation plays an important role in any species. How to release “pain,” especially for a patient with cancer diseases is an important issue in clinical practice. It is however due partially to the show, conduction velocity of pain sensation and the localization in the CNS is not clear; studies on pain have hardly break–through findings. In this investigation, we used CO2 laser as noxious stimulation to induce “pain” in the tail of the rat. The evoked potential was recorded within the rat’s cerebral cortex and analyzed with current-source-density in turn. We found that the closer the recording distance, with respect to the stimulus the shorter the latency of the evoked responses. The maximally evoked responses were at a deeper layer of the cortex, while compared with those obtained from mechanical stimulation. The responsive center located at 0.9 mm in depth from the surface of the cerebral cortex, and a dipole only could be used to model it. To compare the cortical noxious responses evoked from different sources of energy, a noxious mechanical stimulator was developed in this thesis. This device can quantify the force we applied to the body of the experimental animals, and provide an external synchronous output to trigger the data acquisition system. Furthermore, the applied force is also provided as an output connector in analog form for quatilization purpose. This stimulator could be valuable for further studies in our laboratory.