There comes a time in life when we may ask ourselves what is normal brain aging. Who better than memory expert Lee Ryan, Ph.D. to answer our questions?
We asked Lee Ryan, Ph.D, memory expert, associate director, professor and head of the Psychology department at the University of Arizona to answer our questions on normal brain aging.
What happens inside of our brains as we age?
What is fact and what is a myth when it comes to the aging brain?
What is normal brain aging?
Everyone’s brain ages, but it’s not what most people think. The old idea of brain aging is that your neurons, your brain cells, started to die off by the time you were 20 and continued to die through your lifespan.
Now we know that’s not true. In fact, until you are up in your 90s, you lose less than 10 percent of the cells in your brain.
What happens in normal brain aging is not loss of the cells. We know that brain cells change in their structure. They become smaller over time and they actually shrink.
That’s one of the reasons why we see shrinkage of the aging brain. But the good part of that is that Carol Barnes, who is an internationally famous neuroscientist studying aging, found that even though those cells are shrinking, their effectiveness is increased.
So, the connections are boosted between the cells so they can maintain a lot of their function even though they get smaller.
And actually she found two things:
- One is that many of these connections become stronger. They’re compensating for the loss of the numbers of connections between cells.
- But at the same time, she also found that sometimes they kind of misfire. So, young brains are more consistent in their connections. Whereas, in an older brain, the way cells communicate with each other might be a little bit more hit-or-miss.
We can see that, in her Barnes maze, older rats sometimes made a mistake but they didn’t forget where to go. We don’t lose information or memories with normal brain aging.
What happens is that, all of a sudden, we can’t access something. It’s as if the brain didn’t quite make that connection. And then, 10 minutes later, we can remember that person’s name or that piece of information. But 10 minutes before, we couldn’t.
And it’s this hit-or-miss connection that drives people crazy as they get older.
Yes, our brains are aging. But it’s important for people to make a distinction between age-related changes in the brain, which are quite subtle, and age-related cognitive decline caused by brain diseases, like Alzheimer’s or Parkinson’s.
They are not the same.
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What do People Experience in Normal Aging of the Brain?
What we experience in normal brain aging is that we are more distractible, we can get pulled off a topic with ease. For example, you’re telling a story, somebody says something and it takes you off in another direction.
We have difficulty with things like remembering where we put our keys or where we parked the car when we go to the shopping mall. We experience momentary lapses of memory.
One of the most common ones is forgetting somebody’s name. Somebody you know very well. There’s no question that you know that person, you just can’t recall their name. And then 10 minutes later, you remember.
This is completely different than Alzheimer’s disease, where people do lose those memories. These momentary lapses are one hundred percent normal and they happen to people. They happen to us throughout our lifetime, even when we are 20.
But they happen with more frequency as we get older. So, older people notice it more and it gets very annoying but these lapses don’t interfere with how we run our lives. We can take care of ourselves, go shopping, we can do all of those things. They don’t have serious impacts in our daily life – this is very different than the memory problems that arise with Alzheimer’s disease or another dementia.
Aging Brain Facts: How Memory and Thinking Change with Age
What is fact and what is fiction (or a myth) about memory, learning, cognitive abilities and the brain as we age?
1. Fact: A healthy aging brain will shrink with age
As we age, our brain does shrink. The white matter, which is like the electrical cables that connect the various areas of the brain, is not as effective as it used to be. So, the white matter is somewhat damaged as we get older.
When this change of brain cell structure takes place, the brain becomes smaller.
How much does a human brain shrink by age 70?
It depends on the person, but it can shrink in volume as much as 10 percent to 15 percent.
And brain shrinkage doesn’t mean that you’ve lost cells. It means that the size of the cells and the connective tissue, the surrounding tissues that keep the brain healthy, have shrunk.
It’s very different from Alzheimer’s disease where what you lose are the cells themselves due to the disease pathology. What happens in that disease makes those neurons die. That’s not what happens in normal aging of the brain.
If you compared two brains of older adults, one who is normally aging and one who has Alzheimer’s disease, they could be the same size brain. They could each show shrinkage, but it is for very different reasons.
2. Fact: Our neurons don’t die off in large numbers
There is some neuron loss, but it’s way less than what we used to think.
Across your lifespan and even into your 90s, it’s probably at most 10 percent. Which is not a lot because we have millions and millions of brain cells.
3. Fact: It is possible to regenerate brain cells
Another positive fact about the aging brain is that you are still producing new cells as you get older. Right up until the time you die.
As far as we know, the brain can to some extent, regenerate itself. Neurogenesis does happen, even in the hippocampus.
We don’t know enough about how to make it happen faster. Although there is some suggestion that exercise and learning can increase neurogenesis, even in elders.
Being a lifelong learner may actually increase neurogenesis. It probably doesn’t happen to the same extent that it does when your brain is young. But it is still possible to regenerate neurons and for the brain to heal.
Thus, there are ways to help regenerate brain cells for the people who love to be out and about and exercise, and for the people who enjoy learning.
Doing meditation, or tai chi, or exercising regularly, are all likely to decrease stress. Being in social groups or going out and playing cards on Tuesday afternoons with a bunch of friends whose company you enjoy will do the same thing. They’re going to decrease stress.
It’s one of the things that I push for with our precision medicine approach, called precision aging. People need to choose the one they want to do.
Treatments are only as good as your ability to get people to do them. So, telling people that they have to run on a treadmill 30 minutes a day is probably not going to work as well. You want to consider what are the beneficial things you can do that you love doing. Otherwise, it becomes another chore and it adds stress.
So, look for the things that you love to do that are good for you. Or else you’re not going to stick with it.
4. Fact: There is not just one way of aging
We cannot emphasize this enough, the hallmark of aging is individual differences.
Some people will end up having a significant amount of damage to the white matter. Others won’t have much of it, even in their 80s.
Every 20-year-old brain looks about the same. But that’s not true when I look at 70 and 80-year-old brains. You see huge individual differences.
And we know some of that is related to health and to diseases, but it must be related to other things that we don’t yet understand.
Let’s make a parallel to people’s personal appearance as they age. We all know people who seem to never age and others who look older than they are. Why? Because there is no single way of aging.
The same happens to our brains. And 80-year olds are a great example of that.
For the most part, when an 80-year-old comes into my laboratory and does a memory test, on average they don’t do as well as a younger adult. They’re going to have problems every once in a while.
But sometimes one of those 80-year olds comes into the lab and they do just as well on my memory tests as a 20-year-old. What is it about that person that allows them to maintain that level of brain health throughout their lifespan?
That’s what we want to understand.
So. one of the biggest myths about aging is that everybody ages the same. And we don’t. And that’s very important for people to understand. That’s an aging brain fact.
5. Fact: In normal brain aging it takes longer to acquire new information
There are a few things that change in memory with age. One of them is that as you get older, you have a little more difficulty learning new information.
So, when you’re trying to acquire a new skill or new information, it’s going to take you a little bit longer. However, once you acquire it, you will retain it just as well as young people do.
It’s as if the system is getting a little inefficient. But once you gain that knowledge, you maintain that information.
Carol Barnes has shown that the synapses are less consistent. It’s almost like you are trying to learn in a noisy environment. It will take you a little bit longer to get it. You might have to apply a little bit more effort and attention to learn it, but once you do, it will stay. You’re not going to forget.
And that’s very different than what you see in Alzheimer’s disease. Alzheimer’s patients will have difficulty in learning and are also unable to maintain that information, so they forget faster.
In normal aging, we don’t see faster forgetting.
For example, you might be less likely to grasp or maintain or learn new information if you’re in an environment that isn’t conducive. It might be noisy, you might have distractions around, but you can make sure that you’re in a quiet place. You might not do well learning in the middle of Starbucks anymore.
At 20, people study and learn at the cafeteria surrounded by noise. Decades later, with cognitive aging, it’s less likely that they would be able to concentrate there. Some people still can. But most of us need to make sure that we’re in a better environment.
Learning and Repetition
The other thing is, if you’re trying to learn new information, you might have to go back, read it again and review it several times before you really get it. Not that you don’t understand it. The understanding part doesn’t diminish, it’s the absorbing part.
Optimal learning comes from repetition, from practice and from reviewing. But as you get older, it is clear that you may need a little more of that repetition and practice to really become fluent, to absorb the information.
A great example is that 20 or 30 year olds go to work and they park their car. They don’t look around and say “oh, I have to remember, I’m parked right here”. They park their car, they go to work, they come back, they know where their car is.
And for older adults, it’s like “where did I park the car today?” So, there are little things that we might need to do to help us absorb that information. As we get older, we might need to put a little bit more conscious effort to get those things into our brain. And then we won’t forget them.
6. Fact: In normal brain aging it takes longer to retrieve information
There is a second change in memory with aging. For most older adults, when they say they have memory problems, they mean they can’t get the information back out. They can’t retrieve the information.
So, in normal aging, the knowledge is there in your brain, but you may not be able to get at it. And we call that a retrieval problem.
You may not be able to remember the name of someone you know. Or there might be a fact that you are literally searching around in your database and you know it’s in there. But you just can’t get it at that moment, you’re not forgetting. This is why do old people sometimes cannot find words.
This is a big differentiation between Alzheimer’s and normal aging. In Alzheimer’s, you lose that knowledge. In aging, it’s the access that misfires sometimes.
7. Fact: Autobiographical memory is not lost with age
Event memory from your past, what we call autobiographical memory, remains surprisingly intact with age.
You remember things that happened to you in your 20s and maybe even when you were 12 or five just as well as a 30 year old does. You may not get all the details of it, but you remember these events. Autobiographical memory does not decline with age.
Whereas in Alzheimer’s, one of the most difficult things for families to deal with, their loved one begins to forget their past. And that doesn’t happen in normal aging of the brain.
8. Fact: Your brain is not at its sharpest in your 20s
We really do not see much change in memory function and decision making until people are in their 60s. There isn’t a lot of difference in memory performance between those in their 20s, 30s and 40s and even 50s. It’s not until you get into your 60s that you see decreases due to the aging process.
Believing that your brain is at its sharpest in your 20s is a myth. It comes from research that shows graphs where from your 20s onto your 80s your memory performance declines across people’s lifespan. It’s not true.
When you test the same people across their lifespan, instead of testing different groups of people, you don’t lose much memory performance until you reach your 60s or 70s. And that’s when we begin to see changes.
So, when people take the MindCrowd test, would they have scored the same in their 20s or 30s?
When you test 20 year olds and 60 or 70 year olds at the same time, they’re different people. They had very different access to health care and to education. There could be differences in their lives that would account for differences in their memory and attention test results.
But we don’t see those differences in cognition across people’s lifespan. We see that people maintain their cognitive health, their memory function until quite late in life. So, they could have tested the same if they had taken the MindCrowd memory and attention test back then.
Let’s Fight Cognitive Decline
We want to find out how to avoid memory loss as we age. Would you like to help? Be part of the MindCrowd research.
9. Fact: Good for the heart, good for the brain
This fact has a very positive message. The last 20 years of research have shown that when you do things that are good for the heart, you are also doing things that are good for your brain.
Staying socially active, for example. Being what we call “lifelong learners”, somebody who goes out and seeks ways to use their brain in new ways, not just playing video games on a computer, but actually learning. Curiosity and a sense of wonder of the world drive learning.
So, doing things that are good for your heart, are definitely good for your brain as well.
Let’s clarify. Doing all these things do not guarantee that you won’t ever get a disease of the brain, like Alzheimer’s. But they do lower the risk and help maintain your cognitive functions, which is very important.
Even if you never get dementia, being able to stay cognitively active, keep a healthy brain, be able to remember things, problem solve and learn new things is important. Memory and thinking functions affect people’s quality of life as they age.
10. Fact: learning new things does not mean getting a formal education
Learning new things does not imply attending any type of formal education. You may watch a documentary about nature and learn new things about animals and flowers.
A lot of people, as they get older, learn new skills. Some take up woodworking, knitting, oil painting, others become birdwatchers. I was just out for a couple of days with a friend of mine who took up bird watching when she retired. She knows all these birds now and can identify them by the sound, their shape, etc.
All of those activities require you to use your brain and in many cases use your hands, use your body. And that’s perfect when you’re using both your brain and your body. Both your body and your brain can learn.
Normal Brain Aging: Words of Advice to Keep our Brains Healthy
We are beginning to understand that doing things that are meaningful help people keep their brain healthy.
Helping a young person learn to speak English or reading to someone who is blind. Things that not only keep you engaged, but that have a sense of purpose and a sense of meaning.
So many people in our society lose that because you’re supposed to retire and go off and play and not have any responsibilities anymore. And there’s something incredibly important that’s lost in taking that view.
Even if it doesn’t help your brain, you’re way happier. And remember, you get to choose the things that you have a passion for out of the things that are good for your heart and for your brain.
Eighty five percent of people will never experience dementia of any kind. Even if they have a family member who had Alzheimer’s disease. It will increase the risk. But there are no absolutes.
There are a few types of rare genetic variants of Alzheimer’s where you have a very high risk of getting the disease. But for the rest of the population, genetics is just one risk factor among lots of others.
We see more and more people who are living into their 90s and beyond a hundred and they’re not getting Alzheimer’s disease.
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Lee Ryan, Ph.D. is a Professor and Head of the Psychology Department at the University of Arizona. Her research focuses on understanding the basic mechanisms of memory using functional magnetic resonance imaging (fMRI). She also studies how age-related changes in brain structure and function relate to memory changes in older adults, and the importance of cardiovascular health for maintaining “brain health” as we age. Dr. Ryan gives frequent presentations to the public on aging and memory, Alzheimer’s disease, and the positive impact of lifestyle choices on brain health.