Scientist Profile – Professor Michael Hasselmo
Michael Hasselmo, PhD
Professor of Psychological and Brain Sciences
Director of the Center for Systems Neuroscience
Director of the Computational Neurophysiology Laboratory
The Brainbow Bulletin recently sat with Professor Michael Hasselmo to ask him about his research on the circuits involved in episodic memory function—that is, the memory for events that occur at a very specific time and place—and its implications for better understanding neurodegenerative conditions like Alzheimer’s disease.
We also discussed his path to becoming a scientist and his interests and inspirations outside of the laboratory.
Can you briefly describe your research and the goals of your lab?
Our lab is focused on understanding the neural circuits involved in memory function, and specifically the circuits involved in episodic memory function, which includes representing both space and time.
Tell me a little bit more about what that means.
Episodic memory is your memory for events that occur at a very specific time and place. So, what did you do this morning? What did you eat for breakfast? Where did you park your car? You can contrast that with other types of memory, like semantic memory, which is just general facts about the world that aren’t associated with a specific time and place. Episodic memory can involve location on a broad spatial scale, but also location within a room, like, “Where did I put down my car keys two minutes ago?” And it can involve time on multiple scales, time within the day, but also time on the order of minutes or seconds.
Can you give me an example of research you’re conducting in this arena?
One area of research we’re conducting focuses on what are called “egocentric boundary cells.” These are cells located in the retrosplenial and postrhinal cortices that respond when an animal, like a rat or a mouse, is close to a boundary in the environment, like a wall or a ledge.
What kind of impact could research like this end up having on the world at large?
Probably the best example of the impact relative to the world is Alzheimer’s disease, where one of the first things people will note when they talk about impact on their daily life is forgetting where they parked the car in the supermarket parking lot. You park your car in a complex filled with numerous spaces that look very similar, you’re in the store for two hours, and then you come out and you can’t find your car. For some people that can get quite dangerous—if it starts to get late, if the weather’s bad, maybe you don’t even know how to call somebody.
Are you currently working on a project that connects to this kind of impact?
Well, another main theme in my lab is the role of modulation in cortical circuits, and specifically the cell types in what’s called the medial septum. The hippocampus and the entorhinal and retrosplenial cortices are getting all this sensory input, forming memories, and then sending information back to the sensory and motor cortices. And then the medial septum is sitting outside of those information pathways, regulating the flow. It’s kind of saying, “Okay, now is when you’re going to accept and encode new information.” And it’s the loss of that medial septal input that may be one of the mechanisms for impairment in Alzheimer’s disease.
Did you always know you wanted to be a scientist even as a child?
Not necessarily. I remember when I was eight years old, I wanted to be an architect because I liked to draw things. Then as a high school student, I was simultaneously interested in philosophy and in physics. I wanted to explore these big questions about how we think, but I was also interested in having detailed mathematical equations describing physical concepts. And I actively thought about where might those two things link? How do you have thought processes arising from actual physical phenomena in neurons? And that’s what drew me initially to neuroscience in general. As an undergrad, I first went into linguistics because I thought I could explore that kind of connection through language, but then I realized that the amount of data we were able to collect would not be sufficient, whereas studying memory could provide the kinds of data we would need to make the connections I was most interested in.
What’s a fact about you that surprises people?
For people who don’t already know, it’s probably that I play in a rock band, because I’ve noticed that I physically look like a scientist and a professor much more than I look like a rock musician. I play keyboards in a classic rock band that was actually organized by Earl Miller, who was a professor at MIT, and the band has a lot of neuroscience related people in it. The drummer is Brad Dickerson from Mass General, and the guitarist is a guy named Jeff Peppercorn, who is an oncologist now, but he had previously worked with Rudy Tanzi, who does Alzheimer’s research. So that’s at least four of us that are pretty hardcore neuroscientists. And then the lead singer is a clinical psychologist.
*This interview was conducted and edited by Jim Cooney.