Aging brains don't necessarily fade - they adapt

azstarnet.com | Feb 13th 2012

Our brains don't just sit back and deteriorate after age 70. They adapt. Carol A. Barnes, director of the UA Evelyn F. McKnight Brain Institute and a University of Arizona Regents' Professor of psychology and neurology, discussed "The Aging of the Brain" as part of the ongoing "Living Beyond 100" lecture series.

Here, local teachers in a science-writing workshop offer their observations:

Brie Benjamin-Baker: Keep navigating

Whenever I forget why I've walked into a room, I just smirk. I'm only 35. When my mother, in her 60s, does that, she wonders.

Her concern is real. But Barnes had some good news about normally aging adults.

UA researchers have found that where synapses are missing, a person may adapt by allocating more area for a specific memory.

Fifty years ago, we thought spatial memory declined with age because neurons, our main brain cells, were dying off. But actually, older brains have about the same number of neurons and shriveled cells as younger brains.

So why are older brains missing information? The answer lies in synapses, the spaces between nerve cells that let them talk to one another.

Neuron cells communicate through releasing chemicals known as neurotransmitters that attach to the next neuron. Older brains are still sending signals, but as synaptic connections are lost, there is no place to send or receive.

(Brie Benjamin-Baker teaches biology, general science, child development and life skills at the statewide Primavera Online High School.)

Jeff Ofstedahl: No more "old grumps"

Maturing women in my family routinely retreat to what they call Camp WAGO (Women Against Growing Older) for silliness, fun and adventures.

"This sounds a lot like what we call the Positivity Effect," Barnes said. "Most people, as they age, look to the positive side of life and discount the negative."

Games may hold one key to increasing brain function for the aging. Stimulating the brain with virtual-reality games that stimulate pattern-seeking memory pathways increases spatial memory.

With Alzheimer's, what scientists call a tau protein creates fibrous tangles within the hippocampus portion of the temporal lobes. These blockages interfere with the normal pathways the brain uses to recall memories. The resulting neurofibrillary tangle that forms among the neurons shuts down the synaptic relays, and becomes the main reason for the mental impairment.

An estimated 5.4 million Americans live with Alzheimer's. As life spans increase, people living past 90 will have a 30 percent chance of living with Alzheimer's.

(Jeff Ofstedahl is a middle and high school science teacher and K-12 science director at the Center for Academic Success in Sierra Vista.)

Ron Bernee: The mystery box

Our brain is still very much a mysterious black box, despite all the breakthroughs. Barnes' lecture poked some holes in that box, discussing "normal" changes as we become biologically aged, or senescent.

As we age, we lose synaptic connections, the neural fabric of memories. Our older brains compensate by strengthening our remaining connections and by using its property of plasticity.

When our aging hippocampus creates a new cognitive map, it can recruit additional circuits to retrieve a memory. Older people are able to use both brain hemispheres to assist recall, Barnes said.

The 86 billion or so neurons in our brain at birth are all we get. Yet we know that some stem cells can give rise to new cells in the adult brain - a process known as neurogenesis. These adult-born granular cells seem to play a key role in learning and memory formation as we get older, even as older cells may "retire."

More mysteries. And we haven't touched on our sense of purpose, our roles on the planet. So much remains to be uncovered.

The UA writing workshop is supported by Research Corporation for Science Advancement.

On StarNet: Find more coverage of science and technology at azstarnet.com/science

Upcoming "Living Beyond 100" lectures

• "Repair, Regeneration and Replacement Revisited" on Tuesday.

• "Society, Geographic Change and the New Longevity" on Feb. 21.

• "Information and Immortality" on Feb. 28.

All lectures begin at 7 p.m. at Centennial Hall, 1020 E. University Blvd. Parking is available at the Tyndall Avenue Garage, 880 E. Fourth St.

For more information, call 621-4090.

(Ron Bernee teaches biology and AP psychology at Sahuaro High School.)

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