Dr. Sheena Josselyn
Professor University of Toronto & Hospital for Sick Children
Postdoctoral Fellow Yale University and UCLA
PhD in Psychology University of Toronto
When Dr. Sheena Josselyn is asked what her five-year plan is, her answer is simple: “just keep going for five years!” Her goals revolve around staying interested and engaged, which is how she found her way to neuroscience. She was initially on a pre-med track as an undergraduate at Queens University, and enrolled in a psychology course to complete her degree requirements. Once her professor began to talk about brain function, she was hooked: in that class, she realized that the brain is like one big puzzle, and she switched tracks to psychology to begin to tackle understanding it.
After graduating, Sheena sought to blend the worlds of clinical practice and basic research, helping people while also working to solve the puzzle of the brain in the lab. She stayed at Queens University to earn her master’s in clinical psychology, studying feeding and reward behavior in rats while also seeing patients alongside registered psychologists. Ultimately, she chose to pursue a PhD in psychology and neuroscience at the University of Toronto, where she continued to study feeding and reward. While there was not an explicit clinical component to this program, she didn’t stop seeing patients, and pursued clinical work outside of the lab. For the duration of her PhD, she facilitated outpatient group therapy sessions at the Clark Institute of Psychology. There, she worked on issues of recidivism and relapse in populations of sex offenders.
Towards the end of her PhD, Sheena began to feel burnt out on rodent research. “I wanted a job where I could get a manicure!” she jokes, alluding to the demanding hours required of basic research (as well as the constant need to wear nail-covering gloves). She stayed on at the Clark Institute of Psychology to do a one-year transitional postdoc, where she worked with many different clinical populations, but focused primarily on evaluating sex offenders for parole. The experience was intense: “I [initially] thought of myself as Clarisse from Silence of the Lambs,” she recalls. “I’d be Jodi Foster, and I’d have to match wits with these evil geniuses.” Towards the beginning, the experience was indeed very challenging, but by the end, it felt dull. She never met the evil geniuses she thought she would, and instead realized that the component that excited her so much about the brain was missing: in this environment, there was no puzzle to solve. She decided to forego the manicures and get back to the lab.
Sheena’s second postdoc was in Mike Davis’s lab at Yale. Though she loved Yale and was excited to be part of its vibrant scientific community, the Davis lab was preparing to move to Atlanta, and Sheena realized that her interest in gaining more molecular knowledge better aligned with the work of Alcino Silva at UCLA. At the time, her boyfriend (who later became her husband) was also taking a position at UCLA. The confluence of these events motivated her to move to LA and transition to a third postdoc in the Silva lab, where she studied memory engrams in mice. Sheena describes engrams simply as “the bit in the brain that’s really important for memory.” More specifically, the Silva lab looked at the group of neurons that are active both when mice are learning something and when they recall that memory. The lab found that silencing these cells right before prompting mice to recall a memory actually prevented mice from doing so, while artificially activating these cells would make it seem as though mice were recalling the memory unprompted.
While she was excited about her work, “no one else really was.” At the time, there was controversy in the field regarding whether engrams were even worth studying. This was Sheena’s first exposure to the political side of the field of neuroscience: in addition to searching for mechanisms underlying engrams, she and the lab were simultaneously tasked with convincing the field that this topic was worth pursuing. Their approach was to simply keep working at it, and ultimately this strategy paid off. While there is still some semantic debate about engrams, the field has since expanded to include a new generation of neuroscientists studying this aspect of memory.
Sheena’s own lab still works on engrams and memory, but the lab focuses on the memory component of substance abuse. When mice are exposed to cocaine just once, they find it so rewarding that they begin to pair the location of their initial exposure with a feeling of reward. Sheena’s lab finds that silencing the engram in the amygdala corresponding to this experience inhibits this association. She notes that just because silencing one brain region is sufficient to eliminate the recall, it doesn’t mean that the rest of the network is not affected. Instead, she views the amygdala as a key node in a network of brain regions that are involved in emotional learning.
As a professor, Sheena realizes that her graduate school conception of professors “not being real people” is far from her own working reality. While she once thought that professors’ entire worlds revolved around writing grants and doing science, with a husband and an eleven-year-old daughter and a life outside of the lab, she now balances much more than just her research. Towards the beginning of her time as a professor and a new mother, she and her husband, also a scientist at the University of Toronto, would often bring their daughter to work and to conferences with them. Now, while Sheena intentionally tries to compartmentalize (“I don’t give my daughter progress reports, and I don’t ask my graduate students if they need afternoon snacks”), she also acknowledges that this can be difficult, and that some times are more challenging than others. Her biggest challenge right now is keeping the plates spinning through COVID-19—while she tries to forge on with her own work, she also tries to make sure that her trainees aren’t hyper-focusing on productivity, and are instead taking care of themselves. Ultimately, she feels that it is her job to make sure that everyone has the support that they need.
When Sheena looks at the field as a whole, she is excited to see the ways in which women and other underrepresented groups in science are both supporting each other and becoming leaders themselves. While diversity in leadership roles is not increasing as fast as she would like, Sheena firmly believes in disrupting the dominant “male, pale, and frail” academic culture to continue to set it on a path that is more equitable. As a brilliant woman at the top of her field, Sheena is leading by example in forging a path for the next generation of underrepresented neuroscientists.
Listen to Nancy’s interview with Sheena on November 6th, 2020 below or wherever you get your podcasts!
