In search of features that constitute an “enriched environment” in humans: Associations between geographical properties and brain structure

Enriched environments elicit brain plasticity in animals. In humans it is unclear which environment is enriching. Living in a city has been associated with increased amygdala activity in a stress paradigm, and being brought up in a city with increased pregenual anterior cingulate cortex (pACC) activity. We set out to identify geographical characteristics that constitute an enriched environment affecting the human brain. We used structural equation modelling on 341 older adults to establish three latent brain factors (amygdala, pACC and dorsolateral prefrontal cortex (DLPFC)) to test the effects of forest, urban green, water and wasteland around the home address. Our results reveal a significant positive association between the coverage of forest and amygdala integrity. We conclude that forests may have salutogenic effects on the integrity of the amygdala. Since cross-sectional data does not allow causal inference it could also be that individuals with high structural integrity choose to live closer to forest.

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  1. Lovden, M., Wenger, E., Martensson, J., Lindenberger, U. & Backman, L. Structural brain plasticity in adult learning and development. Neurosci Biobehav Rev 37, 2296–2310, (2013).

  2. Rosenzweig, M. R., Krech, D., Bennett, E. L. & Diamond, M. C. Effects of environmental complexity and training on brain chemistry and anatomy: a replication and extension. J Comp Physiol Psychol 55, 429–437 (1962).

  3. Diamond, M. C., Krech, D. & Rosenzweig, M. R. The Effects of an Enriched Environment on the Histology of the Rat Cerebral Cortex. J Comp Neurol 123, 111–120 (1964).

  4. Hebb, D. O. The effects of early experience on problemsolving at maturity. American Psychologist 2, 206–307 (1947).

  5. Nithianantharajah, J. & Hannan, A. J. Enriched environments, experience-dependent plasticity and disorders of the nervous system. Nat Rev Neurosci 7, 697–709, (2006).

  6. Tost, H., Champagne, F. A. & Meyer-Lindenberg, A. Environmental influence in the brain, human welfare and mental health. Nat Neurosci 18, 1421–1431, (2015).

  7. van Praag, H., Kempermann, G. & Gage, F. H. Neural consequences of environmental enrichment. Nat Rev Neurosci 1, 191–198, (2000).

  8. Wurbel, H. Ideal homes? Housing effects on rodent brain and behaviour. Trends Neurosci 24, 207–211 (2001).

  9. Peen, J. et al. Is the prevalence of psychiatric disorders associated with urbanization? Soc Psychiatry Psychiatr Epidemiol 42, 984–989, (2007).

  10. van Os, J., Kenis, G. & Rutten, B. P. The environment and schizophrenia. Nature 468, 203–212, (2010).

  11. Kennedy, D. P., Glascher, J., Tyszka, J. M. & Adolphs, R. Personal space regulation by the human amygdala. Nat Neurosci 12, 1226–1227, (2009).

  12. Beyer, K. M. et al. Exposure to neighborhood green space and mental health: evidence from the survey of the health of Wisconsin. Int J Environ Res Public Health 11, 3453–3472, (2014).

  13. Maas, J., Verheij, R. A., Groenewegen, P. P., de Vries, S. & Spreeuwenberg, P. Green space, urbanity, and health: how strong is the relation? J Epidemiol Community Health 60, 587–592, (2006).

  14. Cassarino, M. & Setti, A. Environment as ‘Brain Training’: A review of geographical and physical environmental influences on cognitive ageing. Ageing Res Rev 23, 167–182, (2015).

  15. Takano, T., Nakamura, K. & Watanabe, M. Urban residential environments and senior citizens’ longevity in megacity areas: the importance of walkable green spaces. J Epidemiol Community Health 56, 913–918 (2002).

  16. Mitchell, R. & Popham, F. Effect of exposure to natural environment on health inequalities: an observational population study. Lancet 372, 1655–1660, (2008).

  17. Alcock, I., White, M. P., Wheeler, B. W., Fleming, L. E. & Depledge, M. H. Longitudinal effects on mental health of moving to greener and less green urban areas. Environ Sci Technol 48, 1247–1255, (2014).

  18. Roe, J. J. et al. Green space and stress: evidence from cortisol measures in deprived urban communities. Int J Environ Res Public Health 10, 4086–4103, (2013).

  19. Craig, J. M., Logan, A. C. & Prescott, S. L. Natural environments, nature relatedness and the ecological theater: connecting satellites and sequencing to shinrin-yoku. J Physiol Anthropol 35, 1, (2016).

  20. Park, B. J., Tsunetsugu, Y., Kasetani, T., Kagawa, T. & Miyazaki, Y. The physiological effects of Shinrin-yoku (taking in the forest atmosphere or forest bathing): evidence from field experiments in 24 forests across Japan. Environ Health Prev Med 15, 18–26, (2010).

  21. Lederbogen, F. et al. City living and urban upbringing affect neural social stress processing in humans. Nature 474, 498–501, (2011).

  22. Streit, F. et al. A functional variant in the neuropeptide S receptor 1 gene moderates the influence of urban upbringing on stress processing in the amygdala. Stress 17, 352–361, (2014).

  23. Haddad, L. et al. Brain structure correlates of urban upbringing, an environmental risk factor for schizophrenia. Schizophr Bull 41, 115–122, (2015).

  24. Bertram, L. et al. Cohort profile: The Berlin Aging Study II (BASE-II). Int J Epidemiol 43, 703–712, (2014).

  25. Kievit, R. A. et al. Distinct aspects of frontal lobe structure mediate age-related differences in fluid intelligence and multitasking. Nat Commun 5, 5658, (2014).

  26. Kennedy, D. P. & Adolphs, R. Social neuroscience: Stress and the city. Nature 474, 452–453, (2011).

  27. Dousset, V. et al. Experimental allergic encephalomyelitis and multiple sclerosis: lesion characterization with magnetization transfer imaging. Radiology 182, 483–491, (1992).

  28. Samson, R. S. et al. Investigation of outer cortical magnetisation transfer ratio abnormalities in multiple sclerosis clinical subgroups. Mult Scler 20, 1322–1330, (2014).

  29. Beaulieu, C. The basis of anisotropic water diffusion in the nervous system – a technical review. NMR Biomed 15, 435–455, (2002).

  30. Baroncelli, L. et al. Enriched experience and recovery from amblyopia in adult rats: impact of motor, social and sensory components. Neuropharmacology 62, 2388–2397 (2012).

  31. Engineer, N. D. et al. Environmental enrichment improves response strength, threshold, selectivity, and latency of auditory cortex neurons. J Neurophysiol 92, 73–82, (2004).

  32. de Vries, S., Verheij, R. A., Groenewegen, P. P. & Spreeuwenberg, P. Natural environments – healthy environments? An exploratory analysis of the relationship between greenspace and health. Environ Plann A 35, 1717–1731, (2003).

  33. Park, B. J. et al. Physiological effects of Shinrin-yoku (taking in the atmosphere of the forest)–using salivary cortisol and cerebral activity as indicators. J Physiol Anthropol 26, 123–128 (2007).

  34. Jenkinson, M., Beckmann, C. F., Behrens, T. E., Woolrich, M. W. & Smith, S. M. Fsl. Neuroimage 62, 782–790, (2012).

  35. Jenkinson, M., Bannister, P., Brady, M. & Smith, S. Improved optimization for the robust and accurate linear registration and motion correction of brain images. Neuroimage 17, 825–841 (2002).

  36. Tzourio-Mazoyer, N. et al. Automated anatomical labeling of activations in SPM using a macroscopic anatomical parcellation of the MNI MRI single-subject brain. Neuroimage 15, 273–289, (2002).

  37. Agency, E. E. Mapping Guide for a European Urban Atlas. (2011).

  38. White, M. P., Alcock, I., Wheeler, B. W. & Depledge, M. H. Would you be happier living in a greener urban area? A fixed-effects analysis of panel data. Psychol Sci 24, 920–928, (2013).

  39. Schermelleh-Engel, K., Kerwer, M. & Klein, A. G. Evaluation of model fit in nonlinear multilevel structural equation modeling. Front Psychol 5, 181, (2014).

  40. Aubert-Broche, B., Evans, A. C. & Collins, L. A new improved version of the realistic digital brain phantom. Neuroimage 32, 138–145, (2006).

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