Give it up for the Hippocampus

How do we know things? How do we know each other, ourselves, names of objects and historical events? How do we know where we left our keys or why we came into a room? We know these things because we have a memory of them, of course.

It’s not unreasonable to assume that most, if not all, seniors are concerned about their memory and their general cognitive function as well. Fortunately, we need not be greatly concerned if we can’t remember why we are standing in the middle of the kitchen or where we put our cell phone. This happens to everyone, not just seniors.

It does happen more frequently with seniors than with younger people though. This age-related increase in mild memory impairment is normal. I sometimes laugh at myself when I’m standing in front of an open refrigerator wondering what it was I needed.

In his book Successful Aging, Daniel Levitin shared a joke that is apparently popular with memory researchers:

Two elderly gentlemen are sitting next to each other at a dinner party.

“My wife and I had dinner at a new restaurant last week,” one of the men says.

“Oh, what’s it called?” the other man says.

“Um…I…I can’t remember.” (Thinks. Rubs chin.)

“Hmm…What is the name of that of that flower that you buy on romantic occasions? You know, it usually comes by the dozen, you can get it in different colors, there are thorns on the stem…?”

“Do you mean a rose?”

“Yes, that’s it!” (Leans across the table to where his wife is sitting.)

“Rose, what was the name of that restaurant we went to last week?”

As is true of other parts of our neurological systems, memory has evolved to help us adapt to the demands of the environment. There are several systems accountable for memory, and each is associated with specific anatomical area(s) of the brain. But before we start drilling down into brain parts, let’s look at how memory works and the types of memories we have.

Types of Memory

We have several different memory systems. Spatial memory allows us to know where we are. Procedural memory helps us remember how to perform simple tasks like using a faucet or activating the turn signal on our car. Short-term memory allows us to remember information we learned just a few minutes ago.

According to Levitin our memory systems form a hierarchy. Spatial, procedural, and short-term memory each use different neural circuits in the brain, and each is vital for daily functioning. But above them, at the top of the hierarchy, are implicit memory and explicit memory.

Implicit memory is the type of memory that we use to perform complex behaviors like playing the piano or tennis. Once these behaviors are learned, we do them automatically without having to think about them or consciously reconstruct them.

Explicit memory, on the other hand, includes two types of memory: semantic memory and episodic memory.

Sematic memory is the memory of general knowledge. This memory includes all the things and information we know but don’t remember learning. It’s knowledge we know so well that we take it for granted. For example, what is the capitol of Russia? Moscow, of course. But when did you learn that?

After so many decades spent acquiring knowledge, we older adults have a lot of information stored in sematic memory. According to professor Alan Castel in his book Better with Age: The Psychology of Successful Aging we sometimes have trouble retrieving general knowledge because we have so many semantic memories in our brains that they become cluttered. The sheer volume makes semantic memories harder to find and affects our recall.

Episodic memory, on the other hand, is the memory of all those things we know from particular events or episodes in our lives. Your wedding, the birth of a child, the funeral of a loved one. We remember these events because we were in them. We were there. What differentiates episodic memories from semantic memories is they have autobiographical components to them.

I recall that in 2007 I was a graduate student sitting in a conference room with three professors giving an oral defense of my dissertation. My committee members asked me a series of questions and asked for explanations of various points I made in my research. When they were done, they asked me to leave the room so they could discuss my work. In about 20 minutes they called me back into the room. I sat down at the table. My Chair stood up and extended her had. I took it and she said, “Congratulations, Dr. Lopez.”

I was so happy I almost started crying. Earning my doctorate at 59 years old was one of the seminal moments of my life. I remember every detail about that room and the members – their names, where they were sitting, even the items on the table in front of them. Heck, I even remember what color blouse my Chair wore that day. That is an episodic memory!

One thing we can glean from the example above is that emotion is a key factor in remembering. Even if the emotion is negative. This is true because the area of the brain that facilitates the storage of emotional memories–the amygdala–is active when we store emotional memories and less so when we store semantic memories. Semantic memory events rely more heavily on another area of the brain–the hippocampus.  

The Aging Brain 

One of the things we do well at when it comes to memory is recalling emotional information. This is probably because these memories carry greater importance for us and because emotions activate the amygdala. And the amygdala tends to continue to perform well even as we age.

On the other hand, the hippocampus, which is the area of the brain responsible for storing all memories, and general memories in particular, declines in volume by about 1% a year after the age of 50.

The hippocampus is a sort of gate keeper for all memories. Even though our memories are not actually stored there, the hippocampus is responsible for the dissemination of information to various areas of the brain where information is turned into memory.

HM: A Case Study

While researching this article, I dug out an old textbook I used when I taught undergraduate psychology–Foundations of Biopsychology  by Andrew Wickens­–and read the chapter on memory. In his book, Wickens describes a classic case study of a person known only as HM, a study from which we learned a great deal about the role of the hippocampus.

HM was born in 1926. At the age of 9 he had a bicycle accident and injured his head. He began having seizures, which increased in severity over time. By his late twenties, HM had such severe seizures that he could no longer work. After several attempts to correct the problem with toxic levels of medication, his doctor decided it would be helpful to remove his hippocampus. (What were they thinking?)

The operation was a success in that it stopped the seizures, but the side effects were disastrous. HM was no longer able to store information into long-term memory. HM suffered a profound case of anterograde amnesia. (Antero means “in front”.) He had good language skills, a good vocabulary, and above-average IQ. He could remember things from his past, but after the surgery he had only short-term memory. He could not consolidate any new long-term memories. A researcher who worked with HM for 40 years had to reintroduce herself to him every time she came to work with him.

What can we learn from this case? Maintaining the health of the hippocampus, is essential if we are to continue acquiring new long-term memories.

What Can We Do?

Fortunately, there are things we can do to support good brain health and even increase the volume of the hippocampus.

In Successful Aging1, Levitin references a book written by a neurologist Scott Grafton, Physical Intelligence: The Science of How the Body and the Mind Guide Each Other Through Life. Grafton points out that when thinking about brain health, the idea of a brain/body dualism is unproductive. The focus should be on the health of the whole organism not just the brain. You can’t separate the two.

Grafton argues that the single factor with the largest effect on mental health is exercise and physical activity in general. “We now have hundreds of trials with thousands of subjects” that show the benefit of physical activity.

In addition to exercise, Grafton also believes we benefit from “…problem solving, social enrichment, mind body coordination, and fresh air.”

So, should we all run out and buy a treadmill? Well, a treadmill may get oxygenated blood to your brain, but that’s not the whole picture. Yes, Levitin points out, “A systematic meta-analysis showed that for adults with mild cognitive impairment, exercise had a significant beneficial effect on memory.” But what about problem solving, social enrichment, and fresh air?

Okay, how about tennis? I don’t know how to play tennis. So, if I took it up, I would have to learn how to play. That would certainly involve mind-body coordination and problem solving as I dash around the court trying to figure out where the ball is going and how I need to swing the racket to be effective. Since, unlike a treadmill, I would need to find people to play with, I would probably make new friends. I think that would constitute social enrichment. And, unlike a treadmill, I would be outside in the fresh air.

Of course, few of us are likely to take up tennis as we age. So is there a happy medium?

The truth is, you don’t have to buy a treadmill or take up tennis to engage in healthful physical activity. Walking works. Just walk at a pace that moves you out of your comfort range to get your blood flowing.

Ideally, walk on a path in a park or in the wilderness. The constant need to make physical and spatial adjustments while walking on an unpaved surface stimulates the neural circuits in the brain and helps keep your navigational skills and memory systems in shape. The area most stimulated by those adjustments is the all-important hippocampus.

Need evidence? A study was done using a group of seniors that walked for 40 minutes three times a week and comparing them to a group of seniors that did stretching exercises three times a week. The study concluded that the average walking group member’s hippocampus increased in size by about 2% after one year.

So, if you want to stay sharp and slow the inevitable decline of your brain, and hence your memory, the best thing you can do is stay active. Do something that will get oxygen to your brain and require you to keep your brain focused on what you’re doing. And try to do it with other people.

Oh, and just for fun, see how a “memory athlete” can remember the first 10,000 digits of Pi.

Ed Lopez, PhD, Love of Aging’s Science Editor is a retired organizational psychologist, university instructor and researcher. His research has been presented at international conferences and published in a peer reviewed journal. Ed is also a decorated Army veteran who served in Vietnam. 

I have prided myself and promoted to anyone who would listen that I am YOLD (young/old). To celebrate my 70th birthday, I ran my first half marathon. At 71, I took Bollywood Dance classes. I have traveled the globe, and last year at the tender age of 72, while in Tibet, I hiked in the Himalayas. (Before you get too impressed, a van took us up to the hiking spot. “The hike” was more like an hour’s walk before reboarding the van. But it was the damn Himalayas, and people could barely breathe.)

A few months later, as I was turning 73, without warning I noticed the first symptom of old person's disease had snuck up on me. I was in the act of standing up after having been seated for an hour, when I caught myself making that sound that the elderly make when standing or sitting down....Ahhhhh, like an exhale. Not the good Ahhhh as in AWESOME.  This was the creepy ahhh of something taking too much effort.

I wasn't about to tell anyone, but I started to have dark thoughts....

Perhaps I was now “on the offramp” – that inevitable gradual decline into morbidity.

Then, WHAM! I received a sign when I stumbled across this quote:

"Old age is the only disease you can catch by imitating its symptoms."

– Mario E. Martinez, Psy. D.

The sun began to shine, birds sang, and my spirit soared. I put myself in reverse and backed right up that offramp. And I vowed to keep a keen and wary eye out for any sign that I might be falling prey to imitating any of the dreaded symptoms. 

What I want to share with you is what I have learned in my brief journey in and out of the dreaded “old persons disease”. Not only have I identified the symptoms, but I have found a cure for each.

4 COMMON REVERSIBLE SYMPTOMS AND THEIR CURE

Symptom #1: Slowed walking and reduced gait.

This is an indicator that you fear you are becoming fragile, losing confidence, and concerned about your sense of balance.

Is it reversible? A study that was done with people from 60 to 90 years old to determine their “swing time”–the time the foot is off the ground when a person is walking. Swing time s realyed to balance and can indicate if someone is becoming frail. The participants were asked to walk so their swing time could be measured as a baseline. Then the subjects were divided into two groups and asked to play a simple computer game.  Unknown to the participants, the game they were playing contained subliminal messages. The first group received positive messages, such as “wise," “astute," and “accomplished."  And the second group received negative subliminal messages such as “senile," “dependent,” and “diseased." After playing the game, the participants were asked to walk again. The group that received negative messages lost swing time and started walking as if they were actually senile, dependent, and diseased. However, the group that received positive messages increased their swing time. This transformation seems to be solely due to their unconscious thoughts. For both groups, sense of self had an immediate impact on bodily function.

Cure #1: Strut your stuff and pick it up!

When walking down the street, the game I play is to spot someone much younger about 10 feet ahead of me, pick up my speed, and pass them. You will be surprised at how fast you can move when there is competition involved. When I pass them, I smile and say to myself, “Eat my dust!”

Symptom #2: Letting younger people help you when you can do it yourself.

I found myself saying “yes” to offers to take people’s seat or to carry something for me. Wasn’t it my time to cruise through life and let others take care of me?

Studies were done on the impact of personal responsibility on the health of residents in a nursing home. One group of residents was told that they could arrange the furniture in their rooms however they wanted, pick which nights to attend a movie, and select plants to keep and care for. A second group of residents, was told that the staff “want to do all we can to help you”. They had their furniture arranged for them, were told which nights to attend movies, and were given a house plant cared for by a nurse. After three weeks, almost all residents in the first group experienced significant improvement in physical and mental well-being; whereas, most participants in the second group declined or stayed the same.

Cure #2:  Don’t let the sweat dry!

Keep active. Stagnation kills. Just say, “No, thank you.” If you can do it, do it.  For bonus points go the extra step and help others. Open doors, give them your seat, and if you are feeling bold, carry their package.

Symptom #3: Not having a reason to jump out of bed each morning

The Japanese call this having an ikigai (pronounced ick-ee-guy): a direction or purpose in life that makes your life worthwhile and towards which you take actions that result in satisfaction and a sense of meaning. Science suggests that beyond just feeling useful, a key need for successful aging is to feel that you have played your part in leaving the world better than you found it.

Gerontologists report that many of the ills associated with aging have been worsened—or even created—by the lack of meaning and purpose in people’s lives. Many older people suffer from psychological pain, far deeper than the physical, as a result of not having a reason to get up in the morning

Cure #3: Get an Ikigai! 

To discover your purpose, you must first find what you love, what the world needs, and what you are good at. Then, find the medium through which you can express that passion. You might want to make art, spend time with children, or volunteer in your community. (See Become a Volunteer by Ed Lopez.)

Symptom #4: “I am too old for that."

From your mouth to God's ears. You’re in real trouble when you (and God) start believing this.

A famous longitudinal study on aging and retirement found that people with a positive attitude toward aging live an average of 7.5 years longer than people who don’t. In fact, people’s perception of aging had a greater effect, positive or negative, on healthy longevity than did lowering cholesterol or blood pressure (which according to the study, increased longevity by 4 years). Perception even had more of an effect than non-smoking, which adds 3 years to your life.

Cure #4: STOP SAYING THAT! 

Put some ridiculously youthful goals on your bucket list. And begin saying, thinking, and being that this leg of the journey is an opportunity for a fresh start to being the person you have always wanted to be.

I am confident you’ve got the point by now. However, I would like to leave you with this final thought: Playing the game of being forever young is a sucker’s game. You are not going to win. Playing the game of being YOLD (Young Old), vital, engaged, active, and having a great attitude toward aging is a game worth playing. 

References:
Ohio Longitudinal Study on Aging and Retirement, 1975-1995 
Nun Study - School Sisters of Notre Dame
Giving Seniors a Subconscious Boost

Candace Shivers is a founder/principal of the Love of Aging movement, along with her good friends and colleagues, Maureen Charles and Liz Dietz.

At the age of 65, following the death of her husband, Candace reinvented herself, launching her current career in the field of aging. She is a champion for older adults living a healthy and vibrant lifestyle and a leader, educator, and expert on the impact of attitude on the quality of life for older adults. Candace currently serves as a Special Projects Manager for Wise & Healthy Aging non-profit providing innovative programming for older adults.

A renowned public speaker, she spent 36 years training people from around the globe in effective communication, leadership, and public speaking – talents she brings to the Love of Aging movement.

Candace is proud to be from Hope, Arkansas, Home of the World’s Largest Watermelon.