Measurements of rat brain activity originating from ultrasound waves in air

Abstract

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.

Ultrasonic Transducers Shaped in Archimedean and Fibonacci Spiral: A Comparison

“…With the advent of ferroelectric polymers [7], new opportunities were offered to scientists in the field of acoustic sensors. Referring to sonar systems, the supremacy of polyvinylidene fluoride (PVDF) has been widely demonstrated for the design and manufacturing of short-range US transducers in the air from 30 kHz up to 100 kHz, which is the same frequency range used by bats [8][9][10][11][12]. The only limitation pertained to the working frequency, which was fixed around a central value, failing to cover the whole band of interest.…”

Biomimetic Sonar for Electrical Activation of the Auditory Pathway

“…Different patterns of echo signals at 50 kHz were encoded into low-frequency signals (a few Hz) according to auditory system transduction and codification processes, in order to bypass the auditory pathway and present the signal directly into the inferior colliculus (IC) of Wistar rats [12][13][14]. IC plays a strategic role in relaying and processing auditory information; indeed, receiving innervation from both the lateral lemniscus and the auditory cortex, the IC 2 Journal of Sensors can be considered as an interface between the lower auditory pathway and the auditory cortex [15].…”