Under great magnification using the electron microscope, it was found that the synapses themselves of the enriched rats’ brains were 50% larger than those of the impoverished rats.

Rats raised with environmental enrichment have thicker cerebral cortices (3.3–7%) that contain 25% more synapses. This effect of environmental richness upon the brain occurs whether it is experienced immediately following birth, after weaning, or during maturity.

Studies demonstrated that rats placed in the enriched environment in the presence of enhanced negative air ions (ion density of 1 x 105) showed a significant decrease in serotonin, an effect not found in the brains of animals living in standard conditions (Diamond et al. 1980).

Results: Rats in the stimulating environment had a thicker cortex and heavier frontal lobe (associated with thinking, planning, and decision-making) compared to rats in the deprived environment. This demonstrations helps show that early environment can have a significant effect on brain growth and development.

Brain: Response to Enrichment When young adult rats were exposed to 30 days of enrichment, however, the entire dorsal cortex, including frontal, parietal, and occipital cortices, increased in thickness.

This study showed the effects of different environments on the brain. Rosenzweig found that rats living in the EC developed a heavier and thicker brain cortex. More specifically, the frontal lobes of the rats were heavier and they had developed more acetylcholine receptors.

-The enriched environment rats had developed more acetylcholine receptors in the cerebral cortex, which are important in learning and memory. -The frontal lobe, which is associated with thinking, planning, and decision making, was heavier in the rats that had been in the enriched environment.

The chapter discusses the early life and discovery of brain plasticity by Rosenzweig. Mark Rosenzweig discovered brain mechanisms of auditory localization and the precedence effect in localization. He is best known for his research to demonstrate neurochemical and neuroanatomical plasticity of the brain.

The impoverished environment – a slightly smaller cage isolated in a separate room in which the rat was placed alone with adequate food and water. The rats’ brains were dissected and various sections were measured, weighed, and analyzed to determine cell growth and the level of neurotransmitter activity.

Neuroplasticity – or brain plasticity – is the ability of the brain to modify its connections or re-wire itself. Without this ability, any brain, not just the human brain, would be unable to develop from infancy through to adulthood or recover from brain injury.

They found that growing up in enriched environments affected activity of the enzyme cholinesterase in the brain. This work led in 1962 to the discovery that environmental enrichment increased cerebral cortex volume.

There are two main types of neuroplasticity:

• Functional plasticity: The brain’s ability to move functions from a damaged area of the brain to other undamaged areas.
• Structural plasticity: The brain’s ability to actually change its physical structure as a result of learning.

From birth to age 5, a child’s brain develops more than at any other time in life. And early brain development has a lasting impact on a child’s ability to learn and succeed in school and life.