Threshold evaluation of electric field perception using optical telemetry technique

An optical telemetry technique was developed which enables us to evaluate physiological responses non-invasively without restraining the subject. The change in diameters of peripheral blood vessels is measured as the change in transmitted intensity of infra-red light across an ear auricle. The signal is transmitted to a remote place using infra-red light diffusely reflected from a ceiling and walls of a room. After the feasibility of this technique was verified with various stress-responses, it was applied to the study of biological effects of electromagnetic fields. A rabbit was exposed to a strong electric field, and the change in its peripheral circulation was detected with this technique. Different field strengths were applied from 5 kV/m - 100 kV/m. Both contraction and dilation of peripheral blood vessels were detected on the exposure to electric fields. The threshold level of the field strength to cause the response was analyzed.