We investigated the relationship between muscle discharge and kinesthetic illusion caused by vibration stimulation of tendons and the effects of touching. To 12 healthy adult subjects under blinded condition, vibration stimulation was given at the distal portion of an extensor muscle of the right forearm；and the kinesthetic illusion expressed as changes in the left wrist joint angle and the electromyograms of the flexor and extensor muscles of the right forearm were recorded. We also investigated the correlation with their emotion and interoception characteristics when touching was performed with the application of vibration stimulation. Kinesthetic illusion triggered by vibration stimulation was observed at the wrist joint. Muscle discharges from the flexor and extensor muscles of the forearm increased, but a positive correlation with kinetic illusion was observed only for the flexor muscles. Touching caused the kinetic illusion to disappear；but it increased muscle discharges from flexor muscles, showing a correlation with interoception characteristics. Muscle discharge activity in the flexor muscles may be involved in the perceptual to motor transformation of proprioceptive information via the cerebral cortex. Psychosomatic correlation through sensory-motor integration at the cerebral cortex level was clarified from the degree of kinesthetic illusion caused by vibration stimulation, its correlation with muscle discharge, and the effects of touching on the phenomena.

This study aims to elucidate the impact of watching three-dimensional forest bathing videos through virtual reality (VR) technology on mental and physical aspects. Specifically, it seeks to investigate how these videos affect mood, walking patterns, and autonomic nervous system function. A total of 18 participants were involved in the study, where they watched a forest bathing VR video, and an electrocardiogram (ECG) frequency analysis was conducted while resting and watching the video. Additionally, mood evaluation using POMS2 and gait motion analysis was conducted before and after watching the video. The findings revealed an increase in the high-frequency component and a decrease in the low-frequency to high-frequency ratio of the ECG during video viewing. Following the video session, scores on the Profile of Mood States for anger-hostility, confusion-bewilderment, tension-anxiety, and overall mood disturbance were significantly lower than after resting condition. Furthermore, walking speed decreased, accompanied by a reduction in the vertical center of gravity shift, pelvic forward or backward tilt, and lower limb joint angle. Consequently, these changes led to a less burdensome gait. Following video viewing, individuals with lower levels of anger-hostility tended to exhibit slower walking speeds. This study found that watching a forest bathing VR video had a psychosomatic correlative effect, resulting in an increase of parasympathetic dominance and the stabilization of mood and walking movements.