Measurements of rat brain activity originating from ultrasound waves in air

Mammals such as rats and bats process high frequency ultrasound waves, through their acoustic nerves, by codifying acoustic signals by means of a complex biological neural network. Similarly, sonar systems based on piezoelectric polymers process ultrasounds in air which, properly elaborated and codified by an artificial neural network, are suitable for stimulating the central nervous system, exactly the same as the ultrasonic information carried along the acoustic nerve in mammals. Our experiments aim at investigating, measuring and characterizing, the reaction of mammals to an external stimulus perceivable by artificial sense organs and not forced by a standard electrical instrumentation. Electroencephalography recordings were performed in order to analyze the cortical effects of the received ultrasonic signal. Preliminary measurements of brain activity demonstrated that electrical information elaborated from ultrasound can be transferred to the brain in order to obtain a response related to both signal characteristics and the stimulated area.