The use of focused ultrasonic waves to modulate neural structures has gained recent interest due to its potential in treating neurological disorders non-invasively. While several papers have focused on the use of ultrasound neuromodulation on peripheral nerves, none of these studies have been performed on the vagus nerve. We present preliminary observations on the effects of focused pulsed ultrasound (FPUS) on the conduction of the left cervical vagus nerve of a Long Evans rat. Ultrasound energy was applied at a frequency of 1.1 MHz, and at spatial-peak, temporal average intensities that ranged from 13.6 to 93.4 W/cm2. Vagus nerve inhibition was observed in most cases. Results of this preliminary study suggested that there is a proportional relationship between acoustic intensity and the level of nerve inhibition.

Figure 1. TOUCHTOKENS are passive tokens that guide users' fingers to specific spatial configurations, resulting in distinguishable touch patterns.

Abstract-Recent developments in on-body interfaces have extended the interaction space of physical devices to the skin of our hands. While these interfaces can easily project graphical elements on the bare hand, they cannot give tactile feedback. Here we present a technology that could help to expand the output capability of on-body interfaces to provide tactile feedback without restricting the skin as an interaction surface. SkinHaptics works by focusing ultrasound in the hand using a phased array of ultrasound transmitters and the acoustic timereversal signal processing technique. We present experimental results that show that this device can steer and focus ultrasound on the skin through the hand, which provides the basis for the envisioned technology. We then present results of a study that show that the focused energy can create sensations that are perceived under the skin and in the hand. We demonstrate the potential of SkinHaptics and discuss how our proof-of-concept device can be scaled beyond the prototype.