Our Plastic-Stable Brains
Gina Turrigiano ’84 revolutionizes neuroscience with her research on brain plasticity.
Imagine a car that could tune itself up. This vehicle changes its own oil, rotates its own tires, and checks its own spark plugs, filters, and hoses. Turns out, you don’t have to imagine this kind of machine—it exists, and it’s the one where you used to do the imagining in the first place.
That’s how Gina Turrigiano ’84 thinks about the human brain: like a machine. But unlike a typical, human-made machine, it’s so complex that it’s usually able to tune itself up without outside interference, and keep changes from destabilizing its circuits. This phenomenon is referred to as homeostatic plasticity, and it means that our brains are flexible enough to constantly adapt to new information and other alterations, but simultaneously stable enough to not fall apart. Gina, as the Joseph Levitan Professor of Vision Science at Brandeis University, has been studying the tension between how our brains can remain both plastic and stable for decades. Not only does this research tell us about how the intricate mechanisms of our brains work and interact, but it also helps us learn how these processes can be interfered with, and has implications for better understanding brain differences. Circuits can either be too excitable, leading to problems like epilepsy, or not excitable enough, which can lead to issues in processing sensory information or in cognitive processes.
When Gina first started at Brandeis, she and her lab made a discovery that revolutionized the field of neuroscience, specifically the branch concerned with brain plasticity. What they discovered was synaptic scaling, a form of homeostatic plasticity that allows neurons to adjust the strength of their synapses to stabilize activity. Gina compares synaptic scaling to a thermostat. If the heat (neuronal excitability) is too low, the brain senses this deviation from the norm and dials up the heat (synaptic strength) to restore the system. If the heat (activity) is too high, the opposite occurs. This helps retain balance in your brain when it comes to learning, memory, your senses, and more. Now the investigates the specific functions of homeostatic plasticity and synaptic scaling, like whether these mechanisms act redundantly, and how and why upward firing rate homeostasis occurs only when the brain is awake and downward firing rate homeostasis occurs only when it’s asleep.
Gina was always interested in biology, but she felt her life change in Prof. Dell Rhodes’s [psychology 1975–2006] physiological psychology class while at ¹û½´ÊÓƵ. “It was like being struck by lightning,” she says. “It brought together so many aspects of what I was interested in. When I took that class, it was like, oh my god, this is where it all comes together.”
For her thesis, she followed that newfound passion and studied sensory inputs to the cerebellum, commuting on the bus with her lab rats to work with neuroscientist Lee Robertson at the Neurological Sciences Institute, with Prof. Steve Arch [biology 1972–2012] as her on-campus adviser. The cerebellum is the part of the brain that is particularly interested in motor coordination, but it’s also been known to receive all kinds of sensory inputs. Gina wanted to find out through her thesis whether or not olfactory—sense of smell—inputs got sent there, too. “The answer seemed to be yes,” she says.
Though she’s come a long way since transporting lab rats on TriMet, Gina still credits ¹û½´ÊÓƵ for showing her how to be an effective science communicator, and for informing her teaching style at Brandeis. “Science is storytelling. When you write a scientific paper, data do not speak for themselves—you have to speak for them,” she says. “What I loved about ¹û½´ÊÓƵ was being able to get a rigorous disciplinary introduction to this broad swath of human endeavor—that was really, really important for me.”
Tags: Alumni, Climate, Sustainability, Environmental, Research