Effects of stimulation by three-dimensional natural images on prefrontal cortex and autonomic nerve activity: a comparison with stimulation using two-dimensional images

Abstract

Empirical evidence suggests that three-dimensional (3D) images of nature promote physiological relaxation in humans by providing more realistic effects compared with two-dimensional (2D) images. However, no studies have evaluated the physiological relaxation effects of nature-derived 3D images on prefrontal cortex and autonomic nerve activity. The present study aimed to clarify the physiological relaxation effects of visual stimulation by 3D flower images on prefrontal cortex and autonomic nerve activity. Nineteen male university students (22.2 ± 0.6 years) were presented with 3D and 2D images of the water lily for 90 s. Prefrontal cortex activity was measured using near-infrared spectroscopy, while autonomic nerve activity was measured using heart rate variability (HRV). Psychological effects were determined using a modified semantic differential method (SD). Compared with visual stimulation by 2D images, that by 3D images resulted in a significant decrease in oxyhemoglobin concentration in the right prefrontal cortex, lower sympathetic activity as calculated by the ratio of the low-frequency to high-frequency HRV component, and a significantly greater realistic feeling as evidenced by higher SD ratings. In conclusion, visual stimulation by realistic 3D floral images promotes physiological relaxation more effectively than the corresponding 2D image.

Relaxation Effect of a 2-Hour Walk in Kumano-Kodo Forest

“…There are many cypress in Japan's forests, and the effect of the scent of hinoki, which is found on the Kodo course, can be considered part of the effect of forest bathing [19]. The visual sense of the forest has also been shown to have a relaxing effect [20]. The current study involved walking for a long time and distance, and found the relaxation effect conventionally shown for walking in a forest compared with urban areas.…”

Comparison of the effects of olfactory stimulation by air-dried and high-temperature-dried wood chips of hinoki cypress (Chamaecyparis obtusa) on prefrontal cortex activity

“…Recent studies have focused on the physiological relaxing effects of nature-derived stimulation [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], and there are several reports on the effects of wood odor on humans [9][10][11]. Miyazaki et al [9] reported that inhalation of Taiwan hinoki oil odor decreases systolic blood pressure.…”

Physiological effects of touching hinoki cypress (Chamaecyparis obtusa)

“…Previous studies have shown that natural environments or nature-derived stimuli, such as forests [36][37][38][39][40][41][42], urban parks [43][44][45], flowers [46][47][48][49][50], and foliage plants [51,52], induce physiological relaxation in humans. Wood is a familiar natural material which we have many opportunities to touch on a daily basis, and it is used for many household objects, such as interior materials of buildings and houses, furniture (desks and shelves), and stationery.…”