The bad : You can’t recall the name of the person you just met. The good : You’re not losing brain cells. “Aging is not a mild form of demential,” says cellular neurobiologist John Morrison, who specialises in aging. Until recently, many scientists thought brain cells died as we aged, shrinking our brains and shedding bits of information that were gone forever. Newer findings indicate that cells in disease free brains stay put; it’s the connections between them that break. With this new perspective has come an explosion of research into how we can help this connections, and our brain function, intact for longer.
Path of information – This is a simplified example of how a healthy brain processes information. The further along the path, the more complex thought becomes and the more vulnerable the area is to age related decline.
- Eyes see something and transmit the image along the optic nerve.
- Visual Cortex identified what the eyes see. This area, and its auditory counterpart, rarely degenerate with age.
- Association areas throughout the brain determine whether the scene is important and how it relates to you. Scientists don’t know how aging affects these areas.
- Hippocampus encodes what you saw into memory. It does this by strengthening synapses. This function appears to decline with age, which is why making and retaining memories become more difficult.
- Prefrontal cortex decides what to do about what you saw. This is the last part of the brain to mature (in our 20s) and the first to decline (after age 50). Because most complex reasoning and planning occur here, some of its synapses are the most nimble and flexible and the thinnest and most fragile. As they break, learning and adapting take longer. Information becomes harder to retrieve, like papers in a file cabinet under a blanket in the attic.
We will discuss the effects of aging on the brain in the following post.