In the year 1962 the American scientist Allan H. Frey carried out experiments with pulsed microwaves, which produced clicking, buzz, hissing or knocking sounds in the heads of people at a distance of up to several thousands yards. In his report, he also wrote that with the change of parameters he can produce pins and needles sensation or perception of severe buffeting in the head and claimed that this energy "could possibly be used as a tool to explore nervous system coding… and for stimulating the nervous system without the damage caused by electrodes" (see this).

In other words, Allan Frey was on the path to finding the way how to manipulate the human nervous system at distance. This was quickly understood by the U.S. Government. For the next two decades Frey, funded by the Office of Naval Research and the U.S. Army, was the most active researcher on the bioeffects of microwave radiation in the country. Frey caused rats to become docile by exposing them to radiation at an average power level of only 50 microwatts per square centimeter. He altered specific behaviors of rats at 8 microwatts per square centimeter. He altered the heart rate of live frogs at 3 microwatts per square centimeter. At only 0.6 microwatts per square centimeter, he caused isolated frogs' hearts to stop beating by timing the microwave pulses at a precise point during the heart's rhythm (see this and this).