Kazuma Aoyama

Saltiness and umami suppression by cathodal electrical stimulation

In this work, we demonstrate that cathodal direct current stimulation to the tongue suppresses the perception of saltiness and umami. This work also investigates the relationship between the amplitude of the stimulation current and the magnitude of the taste suppression. With this technique and extensions to it, any tastes would be able to be reproduced or modified virtually, which would be helpful to reduce excessive intake of substances causing lifestyle disease.

Polka dot: the garden of water spirits

Physical and tangible representations of information have provided users with intuitive interactions in which users can control information through tangible controls using their hands. In these techniques, flexible materials have often been utilized. For example, clay has been used for an intuitive modeling tool which senses the shape of the clay and updates its 3D model data [Piper et al. 2002]. This example enables users to create 3D models without knowledge of computational methods for constructing 3D models. Though these tangible representations of information accept user input, they cannot provide bi-directional physical interactions since their physical properties are not controlled by computers. Therefore, it is difficult to represent dynamic changes of information using physical properties such as motion, size, and color. These tangible user interfaces employ static materials.

Mechanism of inhibitory effect of cathodal current tongue stimulation on five basic tastes

The mechanism by which cathodal current stimulation exerts inhibitory effects on the five basic tastes is revealed herein. The objective of this paper is to successfully achieve inhibition of sweetness by cathodal current electrical stimulation to the tongue, which has not been reported to date, though inhibition of salty and umami perception has been documented. By focusing on the electrophoresis of ions generated by dissolution of taste-inducing substances in water, this paper indicates how human gustation is inhibited by electrical stimulation, which is a key addition to the knowledgebase for achieving control of all five basic tastes.

Modeling the Enhancement Effect of Countercurrent on Acceleration Perception in Galvanic Vestibular Stimulation

Galvanic vestibular stimulation induces virtual acceleration sensation and is expected to be applied in computer games to improve their reality. The acceleration sensation can be enhanced by giving countercurrent which consists of an opposite current part and a forwarding current part. Conventionally, however, the degree of the enhancement is uncontrollable. This study reports that the effect of countercurrent can be modeled by an electrical circuit containing a capacitor and resistors. To model the effect of the countercurrent on the acceleration perception, we investigated the relation between the parameters: the duration and the strength of the opposite current part, of the countercurrent and strength of acceleration perception. The results of our study show that the strength of the acceleration sensation induced by the countercurrent stimulation has a nonlinear correlation with the duration of the opposite current, and the characteristics of the enhancement effect can be estimated using a CR circuit model.

Air Tap: The Sensation of Tapping a Rigid Object in Mid-Air

In developing wearable computing technology, it is often desirable to produce the sensation of tapping a virtual object in mid-air. Such a tapping sensation consists of not only tactile sensations at the fingertips but also force feedbacks to the musculoskeletal system. Therefore, physical interactions with objects ostensibly involve an integration of tactile sensations with force feedback to the musculoskeletal system when perceived objects are contacted. In this study, we propose a method that combines electro-tactile stimulation (ETS) for tactile receptors with functional electro-stimulation (FES) for the musculoskeletal system. The results of an experimental study show that simultaneous perception was reportedly obtained when ETS was delayed by 25 ms after FES when tapping a rigid virtual object.

Countercurrent enhances acceleration sensation in galvanic vestibular stimulation

This study reports that the effect of galvanic vestibular stimulation (GVS) can be enhanced by giving a countercurrent before the normal current stimulation in the forward direction. In order to investigate the effect of the countercurrent on GVS, we applied various kinds of amplitudes and durations of the countercurrent before the normal stimulation. The strength of the effect was measured by the subjective response and body sway. As a result, the enhancing effect by the countercurrent does not only appear in the objective response but also in the subjective reports and we found that the effect of the countercurrent was enhanced in response to the amount of charges of the countercurrent before normal stimulations. Our result implies that there is a capacitor on the current path that enhances the GVS effect by the countercurrent.

Frustration suppression for wellbeing in decision making

This paper assesses subjective and behavioral responses against supraliminal and subliminal visual stimuli during decision making, aiming to enhance human psychological wellbeing. We conducted an experiment in which we assessed variations of response time and subjective task load evaluation, changing visual stimuli. The paper concludes that subjective strength of frustration depends on an amount of attention attraction.