Comparison of the efficacy of pulsed versus CW microwave fields in evoking body movements

Short bursts of 1250-MHz microwave pulses (2-4 pulses of 10 ms duration leading to a midbrain peak-pulse specific absorption rate of 20 MW/kg) have been shown to be effective in evoking body movements in mice. This exposure translates to a specific absorption of 0.2 to 0.4 J/gm for achieving 50% response frequency. Separate experiments using continuous wave (CW) had previously indicated that about twice as much energy was required to elicit similar movements. In recent experiments in which CW and pulsed wave (PW) exposures were carried out on the same mice this result was confirmed. The midbrain bulk temperature rises resulting from these exposures (in the range of 0.1°C) and the comparable efficacy of pulsed versus CW modes suggest that these evoked responses may be based on microthermal effects on the central nervous system