With each issue, Trib+Health brings you an interview with experts on issues related to health care. Here is this week’s subject:
Zoltan Nadasdy is an adjunct assistant professor in the department of psychology at The University of Texas at Austin as well as a researcher at Eötvös Loránd University and the Sarah Cannon Research Institute at St. David’s Medical Center. He recently led a study that redefined fundamental properties of the internal coordinate system.
Editor’s note: This interview has been edited for length and clarity.
Trib+Health: Can you expand on your recent study that redefined fundamental properties of the internal coordinate system?
Zoltan Nadasdy: The cellular basis of our cognitive map of the environment was discovered in the '70s. We have a cognitive model of the environment in our brains, represented by the activity of neurons that we can use as a map. For example, you rely on your neuronal map system to find your car after you’ve parked it in a garage.
The second component — the grid cell scale, or the coordinate system that localizes objects in our environment — was discovered in 2005. The fundamental knowledge in this whole field related to memory functions comes from animal research; around 99 percent of basic research is done on animal models, such as rats. But we had no evidence that these cells in rodents were found in the human brain as well.
So we put our patients in a virtual reality environment for several days while recording the grade structure. We created this computer game that was similar to teleportation — one minute you were exploring the Louvre in Paris, and five minutes later, you were in Egypt, walking among the pyramids and temples. We changed the environment again, and suddenly you were in the backyard of your house.
We found that human brain cells were very different than the rats, with the main difference being that the cells in the human brain were much more flexible. When you’re in your kitchen, you’re making small steps and part of your brain keeps track. But once you’re in the football field or running on a track, the grid expands, and those little steps no longer matter.
Trib+Health: What’s the next step after the study?
Nadasdy: We would like to further investigate because the knowledge we gain from animal studies, even though it’s indispensable, is very limited in how it can be generalized to humans. We cannot address additional questions by doing animal studies.
One thing we are interested in is episodic memory, which is memories of our life in episodes. You put things into the context of time and place, and that’s how we organize memory and our plans. Our coordinate system is a fundamental framework to pin events that make up the fabric of our memory, essentially.
If we can understand how episodic memories are formed, we can hopefully use that as a key for understanding how to fix memories altered by patients with Alzheimer’s or dementia. We can start thinking about how to restore and give the capacity of remembering back.
Trib+Health: What are other things you want to research?
Nadasdy: How does the coordinate system in our brains change when you interact with people? If you’re in a crowded place, does your coordinate system change? How do we navigate inside of buildings? How do we blend things instead of remembering?
Another intriguing question is, how early does the capacity of spatial memory develop? Unless we put kids in MRI scanners, we can’t look into their brains. So we are working with groups to do epilepsy treatment and diagnosis to put electrodes in the brain for monitoring purposes. We can piggyback on those because the electrode is going into the brain regardless, so we might as well use that data and harvest it for our own purposes.