Response of the Brain to Enrichment∗
MARIAN C. DIAMOND
Department of Integrative Biology, 3060 Valley Life Sciences Building
University of California, Berkeley, CA94720, USA
Manuscript received on March 5, 2001; accepted for publication on March 12, 2001;
presented by Leny A. Cavalcante
Before 1960, the brain was considered by scientists to be immutable, subject only to genetic control. In
the early sixties, however, investigators were seriously speculating that environmental influences might be
capable of altering brain structure. By 1964, two research laboratories proved that the morphology and
chemistry or physiology of the brain could be experientially altered (Bennett et al. 1964, Hubel and Wiesel
1965). Since then, the capacity of the brain to respond to environmental input, specifically “enrichment,”
has become an accepted fact among neuroscientists, educators and others. In fact, the demonstration that
environmental enrichment can modify structural components of the rat brain at any age altered prevailing
presumptions about the brain’s plasticity (Diamond et al. 1964, Diamond 1988).
The cerebral cortex, the area associated with higher cognitive processing, is more receptive than other parts
of the brain to environmental enrichment. The message is clear: Although the brain possesses a relatively
constant macrostructural organization, the ever-changing cerebral cortex, with its complex microarchitecture
of unknown potential, is powerfully shaped by experiences before birth, during youth and, in fact, throughout
life. It is essential to note that enrichment effects on the brain have consequences on behavior. Parents,
educators, policy makers, and individuals can all benefit from such knowledge.
Key words: enrichment, cerebral cortex, hippocampus, aging, adult neurogenesis, dendrites.
Can experience produce measurable changes in the
brain? The hypothesis that changes occur in brain
morphology as a result of experience is an old one.
In 1815 Spurzheim asked whether organ size could