A Virtual Reality Application of the Rubber Hand Illusion Induced by Ultrasonic Mid-air Haptic Stimulation

Ultrasonic mid-air haptic technologies, which provide haptic feedback through airwaves produced using ultrasound, could be employed to investigate the sense of body ownership and immersion in virtual reality (VR) by inducing the virtual hand illusion (VHI). Ultrasonic mid-air haptic perception has solely been investigated for glabrous (hairless) skin, which has higher tactile sensitivity than hairy skin. In contrast, the VHI paradigm typically targets hairy skin without comparisons to glabrous skin. The aim of this article was to investigate illusory body ownership, the applicability of ultrasonic mid-air haptics, and perceived immersion in VR using the VHI. Fifty participants viewed a virtual hand being stroked by a feather synchronously and asynchronously with the ultrasonic stimulation applied to the glabrous skin on the palmar surface and the hairy skin on the dorsal surface of their hands. Questionnaire responses revealed that synchronous stimulation induced a stronger VHI than asynchronous stimulation. In synchronous conditions, the VHI was stronger for palmar stimulation than dorsal stimulation. The ultrasonic stimulation was also perceived as more intense on the palmar surface compared to the dorsal surface. Perceived immersion was not related to illusory body ownership per se but was enhanced by the provision of synchronous stimulation.

Особенности лазерно-виброметрического неразрушающего контроля полимерных композиционных материалов с использованием воздушно-связанных ультразвуковых преобразователей

Laser doppler vibrometry is being increasingly used in nondestructive testing (NDT) of polymer composites materials (PCM) and investigation of amplitude-frequency characteristics of acoustic transducers in a wide range of frequencies. The use of air-coupled transducers allows non- contact NDT thus expanding inspection potentials and simplifying, in some cases, test procedures, as well as reducing the environmental impact on test results, to compare to traditional techniques of acoustic NDT, which mainly implement contact stimulation of objects to be tested. In this study, the peculiarities of non-contact ultrasonic stimulation in application to NDT are analyzed by using scanning laser vibrometry. The results of NDT of impact damage in PCM are presented by using some types of air-coupled acoustic transducers, namely, magnetostrictive, piezoelectric and gas discharge.

Circuit-specific sonogenetic stimulation of the deep brain elicits distinct signaling and behaviors in freely moving mice

Sonogenetics uses heterologously-expressed proteins to sensitize neurons to ultrasound, enabling selective, non-invasive, and deep brain stimulation. However, its ability to modulate specific circuits or induce behavioral changes remains to be studied and characterized. Here, we demonstrate that sonogenetics enables efficient activation of well-defined neural circuits by transcranial low-intensity, low-frequency ultrasonic stimulation with high spatiotemporal resolution. Targeted neurons in subcortical regions were made to express a mechanosensitive ion channel (MscL-G22S). Ultrasound could trigger activity in MscL-expressing neurons in the dorsal striatum without increased activation in neighboring regions, and increase locomotion in freely-moving mice. Ultrasound stimulation of MscL-expressing neurons in the ventral tegmental area could activate the mesolimbic pathway to trigger dopamine release in the nucleus accumbens and modulate appetitive conditioning. In MscL-expressing cells, neuronal responses to ultrasound pulses were rapid, reversible and repeatable. Altogether, we show that sonogenetics can selectively manipulate targeted cells to activate defined neural pathways and affect behaviors.

Effective Ultrasonic Stimulation in Human Peripheral Nervous System

ObjectiveLow-intensity ultrasound can stimulate excitable cells in a noninvasive and targeted manner, but which parameters are effective has remained elusive. This question has been difficult to answer because differences in transducers and parameters—frequency in particular—lead to profound differences in the stimulated tissue volumes. The objective of this study is to control for these differences and evaluate which ultrasound parameters are effective in stimulating excitable cells.MethodsHere, we stimulated the human peripheral nervous system using a single transducer operating in a range of frequencies, and matched the stimulated volumes with an acoustic aperture.ResultsWe found that low frequencies (300 kHz) are substantially more effective in generating tactile and nociceptive responses in humans compared to high frequencies (900 kHz). The strong effect of ultrasound frequency was observed for all pressures tested, for continuous and pulsed stimuli, and for tactile and nociceptive responses.ConclusionThis prominent effect may be explained by a mechanical force associated with ultrasound. The effect is not due to heating, which would be weaker at the low frequency.SignificanceThis controlled study reveals that ultrasonic stimulation of excitable cells is stronger at lower frequencies, which guides the choice of transducer hardware for effective ultrasonic stimulation of the peripheral nervous system in humans.