Young brains, old brains: Memory, thinking and aging

God must love us seniors because he is helping us multiply. According to the Central Bureau of Statistics, there are about one million elderly people, aged 65 and over, in Israel – one in every nine people. By the year 2035 there will be 1.66 million. This is a 67% increase, 2.2 times faster than the overall population growth rate. 

Average life expectancy at birth in Israel is 83 years, well above the OECD average. Moreover, a study by the University of Washington, published in the leading medical journal The Lancet, shows “Israelis in the year 2040 are projected to live among the longest, on average, on the planet.”

When asked how he felt on turning 80, Winston Churchill replied that he felt fine, considering the alternative. But do we seniors feel fine? A major issue is how well our brains function. Aging brains often have problems.

To explore the neuroscience of aging brains, I spoke with Dr. Gerry Leisman, a leading neuroscientist affiliated with Haifa University, specializing in rehabilitation. He has co-authored several books, including Neuroplasticity in Learning and Rehabilitation. Our conversation took place as a Zoom webcast organized by Heidi Goldsmith, who heads a group of English-speaking seniors in Zichron Ya’acov.

Dr. Leisman, you hold a professorship in rehabilitation sciences. I recently read a wonderful book by Norman Doidge, ‘The Brain that Changes Itself.’ It is a book of stories about ‘neuroplasticity’ – how the brain can adapt, change and rewire, in a sense. You too have co-authored a textbook on neuroplasticity. How does our amazing organ called the brain rewire itself, after strokes or other damage that may occur?

We all begin life as a single cell, 1/175 of an inch in diameter; 80% of our brain cells (in adulthood, 86 billion neurons) have developed by the age of three and 90%, by age 5. The remaining 10%, especially the frontal lobe, do not develop until the teenage years and later – in females, age 23, and in males 26. So, don’t get married when you’re 20! [The frontal lobe is the part of the brain that controls key cognitive skills, like emotional expression, problem solving, memory, language, judgment, and sex. It is the control panel of our personality and our ability to communicate.]

Unlike other cells in the body, neurons communicate. We say, neurons that fire together, wire together. This is the basis of child development – how children learn. Our brains are far more plastic in childhood than in later life. 

For older people, it takes a greater number of trials to acquire a new skill, than it does for children. Our brains optimize for a particular task. And they can reorganize, i.e. hardwire new connections, if part of the brain is damaged. 

Let’s discuss memory. I find myself lately recalling my kindergarten teacher, Miss Pawson; that’s 72 years ago. But sometimes I find it hard to remember what I did yesterday. Why are seniors’ long memories so strong, and our short memories, weaker?

In fact, short term memories are not really memory. We all have the ability to acquire and store new information. When we repeatedly recall that information, it consolidates into a memory trace. 

As we grow older, it becomes harder and harder to acquire new information, i.e. new memories. This is in part because the part of the brain known as the hippocampus calcifies and degenerates with age. [The hippocampus is a tiny region in the cortex that regulates motivation, emotion, learning and memory; it is only 3.5 cubic centimeters in size, a cube half as long as your little finger on each side]. 

So the essential problem with memory and aging is not a memory problem. It is simply because it becomes harder to learn, with age, and also harder to retrieve information. The information is there, often, but harder for the brain to get to it.

I’ve learned that when I forget a name or a fact, I tell my brain to archive the query and continue to work on it. And if I do not become anxious about it or stressed, sooner or later my brain will come up with the answer. So, yes, the retrieval takes longer – but it does occur! 

So, yes – I myself no longer teach undergraduates. When I did, when I was younger, and when asked a question, I could retrieve the name and title of a key journal article at once. Now I find it harder to do this. Remember, all of our learning is the consequence of the making of connections within our brain. This process degrades when we get older.

Let’s discuss how we seniors can exercise our brains. I work out at the Technion’s fitness center; my stomach muscles almost disappeared during the lockdown, but they are coming back. Use it, or lose it, the saying goes. Is the brain, too, a muscle? Can we exercise it like our biceps? Does ‘use it or lose it’ apply to our brains? And how can we best exercise them?

Our brain is not really a muscle – but we can kind of look at it that way. In terms of evolution, our brains evolved – learned to evaluate danger and flee from it. This means that our cognition (thinking) and our motor ability (movement) are closely linked. Both the decision to flee, and the movement that enables it, occur in our frontal lobe, in the same place. Damage to the frontal lobe has a profound, negative effect.

Participatory sport stimulates cognition. We need to plan our motion (thinking) and then actually do that motion. This is good exercise for the brain. It stimulates cognition. It is better than, say, individual sport where the thinking part is not as important. Movement that involves planning, thinking is best – not just treadmill walking.

This is why social engagement is so important. It stimulates cognition and retards the decline in our motor abilities. Meaningful work does too. Social interaction does help our older brains stay younger.

We seniors are labeled “at risk” and the lockdown has been stricter for us – children and grandchildren were prevented from seeing the elderly living in assisted-living homes, for instance. Will this cause long-term harm?

The really scary thing about this? I don’t know. There are no studies yet. I suspect, there will be changes in the nervous systems of seniors as a result. My guess is, when we do not engage with other people, then there is a more rapid decline in our brains.

So, I deduce there is an operational conclusion. We seniors need to organize. We need to interact with others, our mental health is no less important than our physical wellbeing. We need to find ways to do this safely, but we need to do it!

And on another aspect of our incredible brains: This morning I read about Aiden Gallagher. At age 3 he had terrible epileptic seizures, grand mal [loss of consciousness, violent seizures]. They were life-threatening. The only option was to remove half his brain! The surgeons did this! And today, he is in Grade 5, normal, plays baseball! He has half a brain! This is extreme neuroplasticity.

Aiden had Rasmussen’s syndrome [a very rare, chronic inflammatory neurological disease that affects only one hemisphere (half) of the brain and occurs in children under the age of 10]. We once believed that if our speech centers in the brain were damaged, we lost speech forever. But now, often, after a stroke, speech returns, in six months or so. So, in general, it is not the size of the brain, but it is the brain’s network, wired connections, that is crucial. And those connections can rewire when needed.

Young brains, old brains. What can old brains do that young brains do less well?

Take, for instance, musical instruments. A Japanese violinist and teacher named Shinichi Suzuki figured out that if you don’t start playing an instrument very early, you can’t master it. He invented half-size instruments for very young children. They start learning just the mechanics of violin or cello, at age 3; by age 5 they have mastered it. Then they can begin learning about notes and music, harmony and tempo. This is what young brains can do. 

We seniors, in contrast, achieve wisdom. We have a fountain of knowledge accumulated over the years. We do not have this in our 20’s. We seniors are not cognitively as sharp – but as we analyze our vast experience over the years, we have superior perspectives for decisions.

As we age, the incidence of Alzheimer’s and dementia increases; 3% of people age 65--74, 17% of people age 75-84, and 32% of people age 85 and older get Alzheimer’s. What do we know about it?

For age-related dementia: Diet, exercise, purposeful work, social contacts – all can significantly reduce the risk. Alzheimer’s is different. It is caused by the production of so-called tau proteins [which cause what are called neurofibrillary tangles in the brain]. This damages not just memory, but everything the brain does. It is the progressive destruction of the brain, because it destroys the brain’s interactive capacity – the brain cells’ network. Sleep, language, emotion – they all go. And there is no treatment. 

“Are we getting closer to a solution? Yes! We have a much clearer understanding of the cause. But as yet, there is no treatment.

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Satchel Paige was an amazing African-American baseball player, a pitcher, who played actively in the Major Leagues until the age of 47. Most pitchers consider retiring after they turn 30. His secret, perhaps, is revealed in this aphorism; he asked once how old would you be if you didn’t know how old you was. 

Old brains, perhaps, can remain younger, if we seniors believe it is possible and work actively to make it so. Special thanks to Dr. Leisman for helping us understand this. n