Interest in the human brain is at an all time high with both scientists and the general public reading, learning, and writing more about this great system. There is much discussion and even tension about what the brain can and cannot do, whether it has certain capacities or not, and what can be stated with some confidence and what cannot.

While it is true we need to conduct more, well designed, controlled studies, certain things are true of the brain today:

1. The human brain is the most complicated and brilliant system known.
2. The human brain has plasticity which means it can be shaped, is dynamic, and constantly reorganizing.
3. The human brain generates brain cells in the hippocampus and most likely the olfactory system.
4. Cognition changes as we get older, but there remains great variability particularly at the oldest of age.
5. Proactive lifestyle factors relate to improved brain health.
6. Brain reserve continues to gain support as a mechanism to delay onset of  dementia.

The latter point was reinforced yesterday in a major article in the USA Today (9-2-10) that described a study that will be published in Neurology. A research team at Rush Presbyterian conducted a 12 year study that evaluated the mental activities of 1,157 people 65 years of age and older who did not demonstrate dementia at the start of the study. Study participants were assessed at the beginning of the study and again for Alzheimer’s at the six-year period. After that, each participated was evaluated every three years to measure how often they participated in activities such as reading, listening to the radio, playing games and going to the museum. A five point scale was used with more points earned for more frequent participation in mentally stimulating activities.

Results indicated the rate of cognitive decline for persons without dementia was reduced by 52% for each point on the cognitive activity scale. For persons with Alzheimer’s the average rate of decline per year increased by 42% for each point on the same scale. The research team described their findings using the cognitive construct of “cognitive or brain reserve” which suggests that an active and stimulated brain creates new neural pathways which over time can help to delay onset of neurodegenerative diseases such as Alzheimer’s. This is not a cure.

Researchers were less clear why persons who are mentally active demonstrate a rapid decline once Alzheimer’s manifests. One idea might be that reserve helps to delay onset of Alzheimer’s, but once the disease manifests clinically it is already in an advanced stage with an accelerated rate of decline. The good news for this study is that there is benefit to the brain from remaining mentally stimulated across the lifespan. Brain reserve is something worth building.