Compared to animals placed in impoverished conditions, animals kept in enriched conditions have been found to have heavier, thicker cortices. this is evidence for

The existence of Brain derived neurotrophic factor (Brain growth factor)

Cortices are the layer of unmyelinated neurons (the grey matter) that covers the surface of the cerebral hemisphere. Brain derived neurotrophic factor (BDNF) are proteins which acts on certain neurons of the central nervous system and the peripheral nervous system. BDNF helps to support the survival of existing neurons, and encourage the growth and differentiation of new neurons and synapses found in the brain and the periphery. For the question given above, the existence of the brain growth factors (BDNF) is responsible for the heavier and thicker cortices possessed by animals kept in enriched conditions.

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