Globe-trotting neuroscientist studies how brain encodes spatial information
Lisa Giocomo always loved biology, but took a detour through medicine and psychology on her way to becoming a neurobiologist. She studies grid cells, the brain’s navigation system, to determine how the brain encodes spatial information.
After your alarm clock goes off in the morning, you stumble from your warm, cozy bed to the coffeemaker in your kitchen. You’re barely awake, but somehow you successfully navigate to the kitchen without bumping into walls or furniture. How is this possible? How do you know where to go, even if you’re not really paying attention?
Lisa Giocomo, PhD, assistant professor of neurobiology at the School of Medicine, knows how we get to the coffeemaker while half-asleep: She studies how our brains represent and remember our environment. Her lab focuses on special neurons, called grid cells, which make up an internal “neural navigation system” and give us information about our location in space.
Grid cells are located in the entorhinal cortex, which spans the area just above the ear and includes a region important for short-term memory called the hippocampus. Holding a cup of coffee, Giocomo said that an overly simplistic but useful analogy for grid cells is that they’re the brain’s global-positioning system. Grid cells keep track of physical locations — where we are, where we’ve been and where we’re planning to go.
“Imagine your 16th birthday party: You can remember who was there, what you and they were wearing, and where you were sitting in relation to other people,” she said. “The grid cell system provides the ‘where’ component, the sense of space.”
In fact, grid cells have some major differences with GPS; unlike the electronic device, which only relays information about your position, grid cells also rely on landmarks in the environment. In a recent paper published in Neuron, Giocomo’s lab demonstrated how the mental GPS of a mouse accumulates errors as the animal moves, but corrects itself when the mouse comes into contact with physical barriers.
Scientists can reconstruct an animal’s movements by monitoring grid cell activity in its brain and can track the path it walked, determining whether it wandered throughout a room or walked in a straight line.
A circular career path
Giocomo’s path to joining the neurobiology faculty at Stanford was neither straight nor wandering; it was circular.
“I started out being interested in biology, and then I went into psychology,” she said. “In the end, I came back to neuroscience and biology.”
Giocomo said she always loved biology and from a young age envisioned being a field biologist, like the primatologists Dian Fossey and Jane Goodall. (Giocomo even dressed up as and pretended to be Fossey for a school project in the seventh grade.) Possibly, Giocomo idolized the primatologists because she spent her early childhood playing outdoors in the tiny Colorado mountain town where she was born. Her parents were not scientists, and growing up Giocomo did not know any scientists. When she accepted a scholarship to Baylor University, in Texas, she thought studying medicine would satisfy her love of biology.
I realized treatment options were limited by our understanding of the brain from a biological perspective.
In college, Giocomo worked as a counselor at a local mental health institution for emotionally disturbed adolescents and at a Veterans Affairs hospital, where she did research on depression and schizophrenia. The experiences were formative, she said, contributing to her decision to pursue neuroscience research by majoring in psychology. But Giocomo soon realized she had more questions than answers.
“I enjoyed the human element of the work,” Giocomo said. “By working at the adolescent treatment center, however, I realized treatment options were limited by our understanding of the brain from a biological perspective.”
Giocomo decided to learn more about the underlying causes of mental illness by returning to her roots: her love of biology. After graduating from college, she briefly moved back to Colorado, where she met her future husband, Ian Bratt. The couple moved to Boston, where she attended Boston University as a doctoral student in its neuroscience program. He attended MIT as a doctoral student in electrical engineering and computer science.
In Boston, Giocomo attended a talk by Edvard Moser, PhD, who was speaking about grid cells. Moser and his wife, May-Britt Moser, PhD, shared the 2014 Nobel Prize in Medicine or Physiology with John O’Keefe, PhD, for work on a “position system” in the brain. The Mosers discovered grid cells, which are the GPS-like neurons responsible for sensing where we are in space.
Fascination with grid cells
“I was totally fascinated by grid cells,” Giocomo said, her face lighting up. “I was doing neuron physiology work, but I sat down with my adviser and asked how we could use our techniques to answer questions about grid cells.”
After Moser’s talk, Giocomo and her graduate adviser brainstormed experiments about how grid cells worked at the molecular and cellular levels. As she finished graduate school, Giocomo realized that a natural progression for her research was to take what she had learned and test ideas in animals. The only lab she knew of capable of doing that kind of work was the Moser lab in the Center for Neural Computation, at the Kavli Institute for Systems Neuroscience at the Norwegian University of Science and Technology. Giocomo said convincing her husband to move to all the way to Norway for her postdoctoral studies was not very difficult; he is half-Norwegian.
“It was like magic when I talked about my project idea with the Mosers,” Giocomo said, laughing. “We were there for four years, and we loved it. We almost stayed, with me as part of the center there, but I ended up getting wooed away by Stanford.”
It was like magic when I talked about my project idea with the Mosers.
Giocomo opened her neurobiology lab at Stanford in 2013. The lab studies grid cells, but not just because grid cells are fascinating and recently won the Nobel Prize. Grid cells in the entorhinal cortex make up one of the brain’s systems that has straightforward relationships between input to a neuron and its activity, and between neuronal activity and animal behavior. That means the entorhinal cortex is one of the few brain areas researchers can probe to discover what the neurons are computing and how the animal will behave. Using the grid cell system allows Giocomo to study the brain at the resolution of single neurons, as well as activity in a region of the brain. For example, she can study how individual ion channels, which are specialized holes in a neuron’s cell wall, affect a single neuron, groups of neurons and the behavior those neurons generate.
“We can do a genetic manipulation to look at how the structure of grid cells determines the structure of behavior,” she said. “We can draw large links between cellular biophysiology and what entire brain regions are doing.”
Leading a lab is different than working in a lab, and Giocomo said she now spends more time writing and mentoring than doing actual research. But she enjoys her new responsibilities.
“I discovered that I love writing,” she said, adding that she has authored several “news and views” pieces for scientific journals. “And that I enjoy mentoring and working with the people in my lab. We’re a team.”
Stanford Medicine integrates research, medical education and health care at its three institutions - Stanford University School of Medicine, Stanford Health Care (formerly Stanford Hospital & Clinics), and Lucile Packard Children's Hospital Stanford. For more information, please visit the Office of Communication & Public Affairs site at http://mednews.stanford.edu.