EXPERIENCE INFLUENCES STRUCTURAL PLASTICITY

How does experience alter the brain? For decades, neuroscientists believed that the adult brain responded to experience with changes in physiology, but not in structure. Now we know that the adult brain exhibits a considerable amount of structural plasticity, including the addition of new neurons as well as changes in the connections between existing neurons. These may serve as a substrate for experience-dependent change in the brain.

Gould and her coworkers have recently demonstrated that living in different habitats alters brain structure in adult primates. Elizabeth Gould and Charlie Gross, both professors in the Psychology Department, and Yevgenia Kozorovitskiy, compared the brains of adult marmosets living in semi-naturalistic environments (large enclosures with natural vegetation and opportunities for foraging) with the brains of animals living in standard laboratory cages and found dramatic differences in structural plasticity. Not only did the animals living in the more complex environments have more connections between neurons, but they also exhibited a higher rate of neurogenesis than their cage control counterparts. The changes were observed in the hippocampus and the cerebral cortex, two brain regions important for cognition and regulation of emotion.

Do these results reveal mechanisms by which the brain responds to experience in animals living in the wild? If so, which variables of the complex environment -increased physical activity, social interaction or learning- are involved in these changes? Alternatively, does housing animals in a relatively complex environment simply reverse brain atrophy caused by laboratory cage-induced deprivation? These questions will be the subject of future studies by the group.

< Back