INFLUENCE OF A COMPLEX MAGNETIC FIELD APPLICATION IN RATS UPON THERMAL NOCICEPTIVE THRESHOLDS: THE IMPORTANCE OF POLARITY AND TIMING

• Published in: International journal of neuroscience 2004-10, Vol.114 (10), p.1259-1276
• Main Authors: MARTIN, L. J., KOREN, S. A., PERSINGER, M. A.
• Format: Article
• Language: English
• Subjects: Animals; Behavioral psychophysiology; Biological and medical sciences; Dose-Response Relationship, Radiation; Electrodes; Electromagnetic Fields; Fundamental and applied biological sciences. Psychology; Hyperalgesia - therapy; Male; Materials Testing; Miscellaneous; Pain Measurement; Pain Threshold - radiation effects; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rats; Rats, Wistar; Reaction Time - radiation effects; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Time Factors; Vertebrates: nervous system and sense organs
• ISSN: 0020-7454; 1563-5279; 1543-5245
• DOI: 10.1080/00207450490475689

The application of a weak (1 microTesla) complex magnetic field pattern with a relevant electrophysiological signature produced an analgesic response in rats to thermal stimuli when the pattern was presented once every 4 sec for 30 min through iron-core solenoids. In one experiment, the burst-firing pattern was presented once every 4 s for 30 min and restricted to the positive polarity, negative polarity or a bipolar equivalent. The strongest analgesia occurred when the burst-firing pattern was presented with positive polarity or as the typical bipolar signal. Administrations of the burst-firing pattern once per week for four consecutive weeks produced analgesia that was clearly evident during the first, third, and fourth weeks but not during the second week of treatment. A telephone sensor coil (that can be readily obtained from local electronic shops) was then used instead of the solenoids along with an audio (.wav) file to generate the magnetic field; the analgesia was still apparent. However, when the magnetic pattern was generated from a compact disc source the analgesia was not evoked. The current results suggest that these fields can be generated through simple commercial devices controlled by available computer software.