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.