Harnessing the Senses to Improve Memory

Our memories make us who we are. So says Andrew Budson, MD ’93, a professor of neurology at the Boston University Chobanian & Avedisian School of Medicine.

Since childhood, Budson has been fascinated by the relationship between the mind and the brain. After double-majoring in philosophy and chemistry as an undergraduate to “try to understand that relationship from both ends,” he homed in on cognitive and behavioral neurology as a student at Harvard Medical School. “It seemed a natural fit to study memory, because memory is related to who we are at a very deep and fundamental level,” says Budson, who is also an HMS lecturer on neurology, part-time, at Brigham and Women’s Hospital and the chief of cognitive and behavioral neurology at the VA Boston Healthcare System.

This conviction has driven Budson to research memory loss in Alzheimer’s disease and similar conditions and to write several books offering advice for improving memory and managing memory loss. It also led him to develop a novel theory of consciousness, which asserts that consciousness is a memory system. Explained in short, Budson argues that our actions occur unconsciously, and we remember them a split second later. 

Harvard Medicine magazine talked with Budson about how memories are formed and how the senses might be harnessed to help those recollections stick. The following is an edited version of their conversation.

How do the senses shape memory formation? 

As long as we’re awake and alert, we have information always coming in through our senses. And there are parts of the brain — the hippocampus and some structures related to it — that are taking this information in and potentially getting ready to store it. 

Now, we’ll form a memory for only the parts that we pay attention to. If we pay attention to sensory information, then the hippocampus records that information and we’re able to remember it for the next, say, couple of days. And if it’s something important to us, it can be tagged as important while the memory is being created over the next week or so, which can generate a long-lasting memory that can be stored and retrieved over weeks, months, or years.

The way this works is that our senses generate electrochemical activity — brain cells firing, typically in the cerebral cortex. And there are links from the cerebral cortex to the hippocampus, which takes separate sights, sounds, smells, thoughts, and feelings and binds them together into something coherent. And another part of the hippocampus gives this information an index of sorts so it can be found later.

I recently joined a tea-of-the-month club. Right now, I’m having some black tea from China with a very distinctive smell and flavor. And I feel confident that if I have this same tea in a couple of months, I’ll be able to pull up not only the memory of that tea, but also of this conversation, because my hippocampus is binding together the taste of the tea and the other things happening right now as I drink it.

So is it possible that we can intentionally harness our senses to better remember things? 

Absolutely. Just as a sensory cue like the smell of tea can trigger memory retrieval, you can try to retrieve a certain memory by generating that cue.

Anytime you are forming memories that you want to stay with you, you want them to be as multisensory as possible. Some of my own research has looked at the difference between being able to remember things as a word or remember things as a picture. Our findings suggested that you’ll remember things better if you use as many different sensory modalities as possible.

So, if you are trying to remember a list of grocery items, for example, but you can’t write them down, you’re much more likely to remember the items if you picture them in your mind: picture an apple, a loaf of bread, a bottle of olive oil, and so on. If you say the names of the items out loud — you hear yourself saying them — that will help too, as will thinking about the taste of the items, like the taste of the apple as you bite into it. I must be doing this right now, as my mouth is beginning to water as I’m picturing myself biting into a Honeycrisp apple that I have in the refrigerator, which maybe I’ll get for lunch after this interview.

So, we can use our senses to remember things better. And when we’re retrieving memories, we can try to latch on to any one part of a multisensory experience, and that’s going to allow us to be able to retrieve the memory more easily, faster, and, potentially, in a richer and more detailed manner.

Does this help explain why sometimes smells or songs can jog memories in people with Alzheimer’s and other conditions causing memory loss? 

It’s a very interesting question, and I think there may be different answers. In terms of smells, odor detection is probably the oldest sense that we have, and the hippocampus, which is key in storing memories, is right next to the part of the brain that’s doing all this odor-sensing. Smell can engender some of the strongest retrievals of memories in anyone of any age, including people with Alzheimer’s. 

Now, one of the complicating factors is that smell is often impaired in Alzheimer’s, and we often need to use stronger tastes and smells to elicit the same response. So my advice is, instead of putting in a half teaspoon of cinnamon, for example, put in two teaspoons of cinnamon, to get through some of the deterioration that can occur in diseases like Alzheimer’s.

Music can elicit memories for a couple of different reasons in Alzheimer’s. One reason is that we tend to hear a song, especially a song we like, multiple times. If it’s a book or a poem, maybe we’ll read it once or twice, but with a song, people can hear it hundreds of times over a couple of years. 

Another reason is that music isn’t just causing the brain’s auditory cortex to fire. Music also triggers the emotional centers in the brain and it triggers all of the rhythm centers in the brain. These are directly linked to motor centers in the brain, which is why it’s easy to tap your feet or clap your hands to the musical rhythms. So when we hear music, it is almost as if we’re getting a multisensory experience just from the music, and so it ends up being encoded as a rich experience. 

That makes sense — I’m always surprised by how I still know all the words to songs that I heard on the radio long ago, even if I didn’t particularly like them. I sometimes wish I could replace those memories with other things. 

Well, you’ve just said a very important pearl, which is that although we can influence what we remember and what we forget, for the most part, we don’t have a lot of control. We don’t have nearly as much control as we would like. If you think of what that means about how memory evolved and how our conscious abilities evolved, it is very, very interesting.

Molly McDonough is the associate editor of Harvard Medicine magazine.

Image: John Soares