The biophilia hypothesis – serving as a theoretical framework for this study -- suggests that humans have evolutionary bonds to nature. This theory supports the idea that contact with nature may be essential for brain development in children, as greenspace exposure provides rich opportunities for children to exercise discovery, creativity and risk taking. Evidence suggests that these exercises can positively influence different aspects of brain development and cognitive functioning. This study examined the association between long-term exposure to greenspace and brain structure. The study also investigated (1) the overlap between differences in brain structure and brain regions associated with cognitive function and (2) the association between peak tissue volumes in these regions (i.e. regions associated with cognitive function) and objective measures of cognitive function.
This study utilized data on 253 urban children (age 7-10) who were participants in the Brain Development and Air Pollution Ultrafine Particles in School Children (BREATHE) project conducted in Barcelona (Spain). Satellite imagery, using the satellite-based normalized difference vegetation index (NDVI), was used to estimate the children's lifelong (birth through the time of the study) exposure to residential greenspace. High-resolution 3D magnetic resonance images (MRI) were used to study the children's brain anatomy. Cognitive function was assessed through repeated administrations of computerized working memory and attention tasks.
Results showed exposure to greenness over children's lives was positively associated with the volume of gray matter in the left and right prefrontal cortex and in the left premotor cortex and with the volume of white matter in the right prefrontal region, in the left premotor region, and in both hemispheres of the cerebellum. Some of these regions also partially overlapped with brain regions related to the cognitive test scores (prefrontal cortex and cerebellar and premotor white matter), and peak volumes in these regions were associated with better working memory and reduced inattentiveness.
These results suggest that being raised in greener neighborhoods may have beneficial effects on brain development and cognitive function. Growing up in green neighborhoods not only prompts active, exploratory behaviors associated with brain development and cognitive functioning but also provides some indirect benefits for healthy brain development. Such benefits include reduced exposure to air pollution and noise, increased physical activity, and enriched microbial input. This study adds to the existing literature indicating that exposure to greenspace early in life can result in lifelong benefits.
Research Partner