Brain Drain: Fact or Fiction?
Mental decline is part of aging, right? Wrong! US McArthur Foundation studies on aging have overturned much of the standard thinking on how ageing affects memory and brain power. So, forget those memory myths and find out the truth about brain function.
Myth 1: Memory Gets Worse As You Age
This is not necessarily the case. What are considered to be age-related cognitive changes may be fewer and less pronounced than was previously thought. Recent MacArthur Foundation research findings show that older adults can perform equally as well as younger people on most mental tasks. One MacArthur investigation, which followed a large group of individuals for 28 years, tracked changes in mental fitness, including their ability to:
- use words and numbers accurately
- see relationships between a variety of different shapes
- draw appropriate conclusions from a given set of facts
In the oldest group, which was aged from between 74 and 81, at least half of the participants showed no signs at all of mental decline in these functional areas. This finding was also supported by a 1995 UK university study of 65,000 older men and women, in which scientists reported that IQ slips by a maximum of 5 per cent between the ages of 50 and 80.
Myth 2: Brain Cells Flake Away At the Rate of 50,000 a Day
Scientists believe that brain mass shrinks about 10 per cent during your lifetime, but this doesn’t necessarily lead to diminished brain power. It seems that the complexity and strength of your brain’s circuitry is more significant than brain size.
Researchers now believe that most mental decline is a result, not of shrinking nerve cells, but of reduced density in the dendrites, hair-like filaments that branch out from the ends of the nerve cells and receive and process information coming in. These dendrites develop throughout life, whenever we acquire new knowledge or learn new skills.The only way dendrites can atrophy is if they are not stimulated. So here you go, one more reason to keep your brain active.
If you get proper nutrition, exercise and mental stimulation, and you don’t have Alzheimer’s disease, then dendrites in the aging human brain can actually grow longer and denser. Denser dendrites may help you:
- better understand the long-term consequences of decisions
- know when and where to get more information before arriving at a decision
- be more sensitive to religious and cultural issues
- realise that issues are complex and that no course of action you take is necessarily perfect
Myth 3: Once You Lose It, It’s Gone
Scientists long believed that brain-cell loss or damage was permanent, but new studies refute the idea that we’re born with all the neurones we’ll ever have. Scientists at the US Salk Institute in California have found compelling evidence for neurogenesis, the birth of neurones, in the adult human brain. Researchers aren’t certain how or even whether these newborn cells function in learning and memory processes, but it does seem possible. Similar investigations into the brain’s capacity to regrow or heal itself are ongoing in labs globally. Researchers at the Massachusetts Institute of Technology have reconfigured the brains of newborn ferrets so their eyes were connected to regions of the brain where hearing normally develops. The result? The ferrets went on to develop fully functioning visual pathways in auditory brain tissue. The implication is that functional hearing, sight and touch-and perhaps language and emotions-are not completely isolated in specialised regions of the brain, or at least those regions are not set in stone at birth.