Neurobiological effects of urban built and natural environment on mental health: systematic review

Although rapid global urbanization improves people in many ways, it also increases the prevalence of major mental disorders in urban communities. Exposure to natural surroundings, whether real or virtual, on the other hand, has been found to reduce arousal and stress. The purpose of this study is to provide an overview of the existing literature on how brain function changes when exposed to natural and urban settings. As a highly effective technique for determining human brain activity, this review considers literature using neuroimaging techniques, i.e., electroencephalography (EEG), functional magnetic resonance imaging (fMRI), and functional near-infrared spectroscopy (fNIRS). SCOPUS and PubMed were searched for peer-reviewed literature published prior to September 2021. Twenty-six sources were included, returning 263 papers; 18 empirical articles published from 1991 to 2021 were included in the final synthesis. EEG findings were generally consistent with those obtained from fMRI/NIRS data. Natural settings were linked to greater alpha EEG values and fewer demands on information processing and stronger functional connectivity in fMRI/NIRS studies, which indicate feelings of relaxation and restoration. These findings offer a better understanding of the functional activities during environmental exposures and also imply that nature exposure improves cognitive functions and mental health.