Environmental enrichment, new neurons and the neurobiology of individuality


‘Enriched environments’ are a key experimental paradigm to decipher how interactions between genes and environment change the structure and function of the brain across the lifespan of an animal. The regulation of adult hippocampal neurogenesis by environmental enrichment is a prime example of this complex interaction. As each animal in an enriched environment will have a slightly different set of experiences that results in downstream differences between individuals, enrichment can be considered not only as an external source of rich stimuli but also to provide the room for individual behaviour that shapes individual patterns of brain plasticity and thus function.

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Fig. 1: The enriched environment paradigm and its variations.
Fig. 2: Parameters, mechanisms and variables in the enriched environment.
Fig. 3: Mechanistic perspectives on enriched environment.


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The author thanks the members of his group who in many discussions contributed to shaping the ideas presented in this article.

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Nature Reviews Neuroscience thanks A. Hannan and the other anonymous reviewers for their contribution to the peer review of this work.

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Adjuvant manipulation

A supportive treatment that is applied alongside a primary (therapeutic) intervention.


A school of thought in cognitive psychology that treated higher brain functions and especially learning as consequence of more or less simple input–output relationships (‘psychic reflexes’).

Emergent properties

Properties that arise in complex systems and go beyond what can be predicted from knowing the functions of the parts of that system.

Enriched environments

(ENRs). Defined housing conditions for laboratory animals that are richer in stimuli than standard conditions.


The processes by which members of a population become different from each other.

Outbred strains

Laboratory strains of animals that preserve a certain level of genetic inhomogeneity (as opposed to inbred strains, in which animals are genetically identical).

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Kempermann, G. Environmental enrichment, new neurons and the neurobiology of individuality. Nat Rev Neurosci 20, 235–245 (2019). https://doi.org/10.1038/s41583-019-0120-x

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