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

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.

Physiological effects of viewing fresh red roses.

OBJECTIVES: The present study aimed to clarify the effects of viewing fresh roses on prefrontal cortex activity, autonomic nervous activity and subjective assessments of psychological relaxation. DESIGN: A crossover design, in which each experimental group crosses over from one treatment to another, was used. SETTING AND INTERVENTIONS: A total of 15 female university students (mean age 21.7±1.1years) viewed fresh roses for 3min; the control consisted of no experimental stimulus. MAIN OUTCOME MEASURES: Physiological effects on prefrontal cortex activity were determined by near-infrared time-resolved spectroscopy, which was assessed by measuring oxyhemoglobin (oxy-Hb) concentration in the left and right prefrontal cortex; effects on autonomic nervous activity were assessed by measuring heart rate variability (HRV) and heart rate. Modified semantic differential method and Profile of Mood States were used to determine subjective evaluations. RESULTS: Viewing roses induced: 1) a significant decrease in oxy-Hb concentrations in the right prefrontal cortex; 2) a marginally significant decrease in ln[LF/(LF+HF)] of HRV, which is associated with sympathetic nervous activity; 3) a significant increase in perceptions of feeling 'comfortable,' 'relaxed,' and 'natural;' and 4) a significant improvement in mood state. CONCLUSIONS: These findings indicate that visual stimulation with roses induces physiological and psychological relaxation.

Effect of stimulation by foliage plant display images on prefrontal cortex activity: a comparison with stimulation using actual foliage plants.

BACKGROUND AND PURPOSE: Natural scenes like forests and flowers evoke neurophysiological responses that can suppress anxiety and relieve stress. We examined whether images of natural objects can elicit neural responses similar to those evoked by real objects by comparing the activation of the prefrontal cortex during presentation of real foliage plants with a projected image of the same foliage plants. METHODS: Oxy-hemoglobin concentrations in the prefrontal cortex were measured using time-resolved near-infrared spectroscopy while the subjects viewed the real plants or a projected image of the same plants. RESULTS: Compared with a projected image of foliage plants, viewing the actual foliage plants significantly increased oxy-hemoglobin concentrations in the prefrontal cortex. However, using the modified semantic differential method, subjective emotional response ratings ("comfortable vs. uncomfortable" and "relaxed vs. awakening") were similar for both stimuli. CONCLUSIONS: The frontal cortex responded differently to presentation of actual plants compared with images of these plants even when the subjective emotional response was similar. These results may help explain the physical and mental health benefits of urban, domestic, and workplace foliage.

Physiological and Psychological Effects of a Walk in Urban Parks in Fall.

In recent times, attention has been focused on the role of urban green spaces in promoting human health and well-being. However, there is a lack of evidence-based research on the physiological effects of walking in urban green areas. This study aimed to clarify the physiological and psychological effects of walking in urban parks during fall. Twenty-three males (mean age 22.3 ± 1.2 years) were instructed to walk predetermined 15-min courses in an urban park and in a nearby city area (control). Heart rate and heart rate variability were measured to assess physiological responses, and the semantic differential method, Profile of Mood States, and State-Trait Anxiety Inventory were used to measure psychological responses. We observed that walking in an urban park resulted in a significantly lower heart rate, higher parasympathetic nerve activity, and lower sympathetic nerve activity than walking through the city area. In subjective evaluations, participants were more "comfortable," "natural," "relaxed," and "vigorous" after a walk in the urban park. Furthermore, they exhibited significantly lower levels of negative emotions and anxiety. These findings provide scientific evidence for the physiological and psychological relaxation effects of walking in urban parks during fall.

Physiological and psychological effects on high school students of viewing real and artificial pansies.

The relaxation effects of gardening have attracted attention; however, very few studies have researched its physiological effects on humans. This study aimed to clarify the physiological and psychological effects on high school students of viewing real and artificial pansies. Forty high school students (male: 19, female: 21) at Chiba Prefectural Kashiwanoha Senior High School, Japan, participated in this experiment. The subjects were presented with a visual stimulation of fresh yellow pansies (Viola x wittrockiana "Nature Clear Lemon") in a planter for 3 min. Artificial yellow pansies in a planter were used as the control. Heart rate variability was used as a physiological measurement and the modified semantic differential method was used for subjective evaluation. Compared with artificial pansies, visual stimulation with real flowers resulted in a significant decrease in the ratio of low- to high-frequency heart rate variability component, which reflects sympathetic nerve activity. In contrast, high frequency, which reflects parasympathetic nerve activity, showed no significant difference. With regard to the psychological indices, viewing real flowers resulted in "comfortable", "relaxed", and "natural" feelings. The findings indicate that visual stimulation with real pansies induced physiological and psychological relaxation effects in high school students.

Physiological and Psychological Effects of Viewing a Kiwifruit (Actinidia deliciosa 'Hayward') Orchard Landscape in Summer in Japan.

The physiological and psychological relaxation effects of viewing a kiwifruit (Actinidia deliciosa 'Hayward') orchard landscape were investigated. Seventeen Japanese adult females (46.1 ± 8.2 years) viewed a kiwifruit orchard landscape or a building site (control) for 10 min. The heart rate variability and heart rate were determined. The modified semantic differential method and the short-form Profile of Mood States were used to assess the psychological effects. Compared with viewing the building site, viewing the kiwifruit orchard landscape resulted in a significant increase in the parasympathetic activity, a marginally significant decrease in the heart rate, a significant increase in "comfortable", "relaxed" and "natural" feelings and a significant improvement in mood states.

Effects of olfactory stimulation with perilla essential oil on prefrontal cortex activity.

OBJECTIVES: To clarify the effect of olfactory stimulation with perilla essential oil on human prefrontal cortex activity using near-infrared time-resolved spectroscopy. DESIGN: Single-center prospective study. METHODS: Nineteen female university students (mean age, 21.6 ± 1.5 years) participated in the study. Perilla essential oil was used as an olfactory stimulant and air as a control. Oxyhemoglobin concentrations in the prefrontal cortex were measured by using near-infrared time-resolved spectroscopy when the participants were presented with the stimulant or control. Emotional effects were subjectively evaluated by using a modified semantic differential method. RESULTS: Olfactory stimulation with the perilla essential oil significantly reduced the oxyhemoglobin concentration in the prefrontal cortex. No significant differences in the feelings of comfort or relaxation, which strongly reflect human mental status, were observed between the perilla essential oil and control periods. CONCLUSIONS: Olfactory stimulation with perilla essential oil reduced prefrontal cortex activity, thereby inducing physiologic relaxation.

Effects of olfactory stimulation with rose and orange oil on prefrontal cortex activity.

OBJECTIVES: People have been aware of essential oils, which are derived from plants, for a long time. Recently, we have become interested in physiological and subjective effects of daily exposure to essential oils. The primary aim of the present study was to clarify effects of olfactory stimulation with rose or orange oil on prefrontal cortex activity; subjective evaluations of relaxation were also determined. SETTING AND INTERVENTIONS: Subjects were exposed for 90s to air impregnated with either rose or orange essential oil. As a control, subjects wore the same device but inhaled only unimpregnated air. The three stimuli were randomly presented to each subject. MAIN OUTCOME MEASURES: Physiological effects were determined by near-infrared time-resolved spectroscopy and a modified semantic differential approach was used to determine subjective evaluations. RESULTS: The study participants were 20 female university students (mean age 22.5±1.6 years). Olfactory stimulation by rose or orange oil induced: (1) a significant decrease in oxyhemoglobin concentration in the right prefrontal cortex and (2) an increase in "comfortable," "relaxed," and "natural" feelings. CONCLUSION: These findings indicate that olfactory stimulation by rose or orange oil induces physiological and psychological relaxation.

Effect of olfactory stimulation by fresh rose flowers on autonomic nervous activity.

OBJECTIVE: To clarify the effect of olfactory stimulation by fresh rose flowers, which exude a strong fragrance, on heart rate variability. SETTINGS: A chamber with an artificial climate maintained at 25°C with 50% relative humidity and 230 lux illumination at the Center for Environment, Health, and Field Sciences, Chiba University, Japan. PARTICIPANTS: Nineteen female university and graduate students (mean age, 21.6±1.5 years; age range, 19.0-26.0 years). INTERVENTIONS: Fresh rose flowers as an olfactory stimulant, with air as a control. OUTCOME MEASURES: Heart rate variability and subjective evaluations. The power levels of the high-frequency (HF) (0.15-0.40 Hz) and low-frequency (LF) (0.04-0.15 Hz) components of heart rate variability were calculated by the maximum-entropy method. The HF power was considered to reflect parasympathetic nervous activity. The LF/HF power ratio was determined to reflect the sympathetic nervous activity. A modified semantic differential method was used to perform subjective evaluations. RESULTS: Fresh rose flowers induced (1) a significant increase in parasympathetic nervous activities and (2) an increase in "comfortable" and "natural" feelings. CONCLUSION: The findings indicated that olfactory stimulation by fresh rose flowers induced physiological and psychological relaxation.

Physiological and psychological responses of young males during spring-time walks in urban parks.

BACKGROUND: It is widely believed that contact with the natural environment can improve physical and mental health. Urban green spaces may provide city residents with these benefits; however, there is a lack of empirical field research on the health benefits of urban parks. METHODS: This field experiment was performed in May. Seventeen males aged 21.2 ± 1.7 years (mean ± standard deviation) were instructed to walk predetermined 15-minute courses in an urban park and a nearby city area (control). Heart rate and heart rate variability (HRV) were measured to assess physiological responses. The semantic differential (SD) method, Profile of Mood States (POMS), and State-Trait Anxiety Inventory (STAI) were used to measure psychological responses. RESULTS: Heart rate was significantly lower while walking in the urban park than while walking in the city street. Furthermore, the urban park walk led to higher parasympathetic nervous activity and lower sympathetic nervous activity compared with the walk through the city street. Subjective evaluations were generally in accordance with physiological reactions, and significantly higher scores were observed for the 'comfortable', 'natural', and 'relaxed' parameters following the urban park walk. After the urban park walk, the score for the 'vigor' subscale of the POMS was significantly higher, whereas that for negative feelings such as 'tension-anxiety' and 'fatigue' was significantly lower. The score for the anxiety dimension of the STAI was also significantly lower after the urban park walk. CONCLUSIONS: Physiological and psychological results from this field experiment provide evidence for the physiological and psychological benefits of urban green spaces. A brief spring-time walk in an urban park shifted sympathetic/parasympathetic balance and improved mood state.

A review on bioactivities of perilla: progress in research on the functions of perilla as medicine and food.

Perilla is a useful pharmaceutical and food product and is empirically consumed by humans. However, its properties have not been evaluated extensively. In this review, we summarize the progress made in research, focusing on the bioactivities of perilla. There are many in vitro and animal studies on the cytostatic activity and antiallergic effects, respectively, of perilla and its constituents. However, its influence on humans remains unclear. Hence, investigating and clarifying the physiological effects of perilla and its constituents on humans are imperative in the future to adhere to the ideals of evidence-based medicine.

Physiological and psychological effects of walking on young males in urban parks in winter.

BACKGROUND: Interaction with nature has a relaxing effect on humans. Increasing attention has been focused on the therapeutic effects of urban green space; however, there is a lack of evidence-based field research. This study provided scientific evidence supporting the physiological and psychological effects of walking on young males in urban parks in winter. FINDINGS: Subjects (13 males aged 22.5 ± 3.1 years) were instructed to walk predetermined 15-minute courses in an urban park (test) and in the city area (control). Heart rate and heart rate variability (HRV) were measured to assess physiological responses. The semantic differential (SD) method, Profile of Mood States (POMS), and State-Trait Anxiety Inventory (STAI) were used to determine psychological responses.Heart rate was significantly lower and the natural logarithm of the high frequency component of HRV was significantly higher when walking through the urban park than through the city area. The results of three questionnaires indicated that walking in the urban park improved mood and decreased negative feelings and anxiety. CONCLUSIONS: Physiological and psychological data from this field experiment provide important scientific evidence regarding the health benefits of walking in an urban park. The results support the premise that walking in an urban park has relaxing effects even in winter.

Evaluation of titanium dioxide as a pharmaceutical excipient for preformulation of a photo-labile drug: effect of physicochemical properties on the photostability of solid-state nisoldipine.

To characterize the photocatalytic activity of TiO2 via solid-state reaction, the relationship between the physicochemical properties and photocatalytic activity of TiO2 was investigated and estimated from the results of photodegradation of nisoldipine. The photodegradation of nisoldipine was significantly enhanced by addition of TiO2. Two degradation products, nitroso-phenylpyridine derivative and nitro-phenylpyridine derivative, were formed. The degree of photocatalytic activity of TiO2 was quite different between the various types of TiO2 investigated, even when the crystalline phase was the same. As a result of the investigations into the relationship between the photocatalytic activity and physicochemical properties of TiO2, it was found that for the rutile form the photocatalytic activity has good correlation with specific surface area of TiO2, but poor correlation with water loss on drying of TiO2. However, for the anatase form, the photocatalytic activity has good correlation with water loss on drying of TiO2, but poor correlation with specific surface area. Moreover, it was found that the crystallinity of TiO2 has a moderate correlation with the photocatalytic activity of both crystal forms of TiO2. These results suggest that a degree of photocatalytic activity of TiO2 depends on the various physicochemical properties of each type of TiO2 investigated.