- 著者
-
南谷 晴之
萩田 紀博
- 出版者
- 一般社団法人 日本生体医工学会
- 雑誌
- 医用電子と生体工学 (ISSN:00213292)
- 巻号頁・発行日
- vol.18, no.4, pp.256-263, 1980-08-30 (Released:2011-03-09)
- 参考文献数
- 31
In this study, a neural network model is proposed to obtain -the numerical description of pain mechanisms. The model simulates peripheral receptors, afferent L- and S-fibers and the receptive cells of the spinal cord area Adaptation effect and conduction velocity of each fiber are considered in the model. The activities of peripheral and spinal cord neural cells are represented by the Wilson-Cowan's differential equation, considering the ongoing activity of neurons. Pain and touch sensibilities are estimated by the firing activities of lamina V (Transmission, T) cells and lamina IV cells, respectively.The results of model simulation have been obtained for single square-wave pulse and periodic pulse sequences applied on peripheral receptors. The duration of initial bursts of T and IV cells, which occur soon after the beginning of stimulation, depends on the stimulus intensity and approaches a plateau with increasing intensity. In case the stimulus intensity is increased above the threshold of S-fibers, secondary burst of T cells appears about 50 msec after the stimulation, which is equivalent to the conduction time of S-fibers from the periphery towards the spinal cord cells. High-frequency and high-intensity stimulation gives the typical firing patterns of pain modality, represented by the high secondary burst of T cells which continues during the stimulation. From the results of periodic pulse stimulation, the so-called pain and absolute threshold characteristics have been obtained and have been compared with the results of cutaneous electrical stimulation. Both results are shown by quite a similar relationship between stimulus pulse frequency and stimulus intensity and their characteristics are given by the power function's law of frequency and intensity.The proposed neural network model mimics the pain modality very well, and the results of simulation are in good agreement with some of physiological and experimental results.