Beth Stevens, a North­eastern alumna and pio­neering neu­ro­sci­en­tist, has spent the better part of her research career trans­forming our under­standing of how the brain is wired.

In a break­through study in 2012, Stevens dis­cov­ered that cells called microglia not only pro­tect the brain by reducing inflam­ma­tion, but also “prune” bad synapses during brain devel­op­ment, ensuring that the brain is wired prop­erly. The star­tling rev­e­la­tion also indi­cated that dis­eases such as Alzheimer’s, Huntington’s, and schiz­o­phrenia could stem from impaired microglial func­tion and abnormal acti­va­tion of this pruning mechanism.

A major ques­tion still is what makes synapses vul­ner­able? Why do we lose our synapses?” said Stevens, an assis­tant pro­fessor in the Depart­ment of Neu­rology at Har­vard Med­ical School and the F.M. Kirby Neu­ro­bi­ology Center at Boston Children’s Hos­pital. “If we could under­stand how synapses get lost, we may be able to think about novel approaches and novel ther­a­peu­tics to pro­tect those synapses.”

She was addressing a standing-​​room only crowd of stu­dents, fac­ulty, and staff in the event space on the 17th floor of East Vil­lage on Thursday evening, reflecting on her life’s work before engaging in a lengthy con­ver­sa­tion with North­eastern Pres­i­dent Joseph E. Aoun. “Even though all of these dis­or­ders, ranging from Alzheimer’s to Huntington’s to schiz­o­phrenia, seem so dif­ferent from one another, we hypoth­e­size there may be some common path­ways or common mech­a­nisms that might underlie this synaptic loss,” she said. “And if so—if we can under­stand what that is—this may pro­vide new insights into therapies.”

Here are four take­aways from the event:

Microglia, synapses, and neu­ro­log­ical disorders

Microglia account for 10 per­cent of cells in the human brain, Stevens said, but she and other neu­ro­bi­ol­o­gists haven’t always studied them. “They’re immune-​​derived,” she explained, “so it wasn’t thought that these cells could play a normal role during development.”

That line of thinking has since gone out the window, how­ever, par­tic­u­larly after sci­en­tists dis­cov­ered that one of microglia’s pri­mary roles is to “survey” the brain’s synapses. As Stevens put it, “Now we’re thinking about these cells in a com­pletely dif­ferent way.”

She and her lab col­leagues won­dered whether microglia could be involved in the pruning process. They knew these cells were par­tic­u­larly good at “eating things,” as Stevens put it, and they won­dered whether they might be nib­bling at synapses, leading to neu­ro­log­ical disorders.

We hypoth­e­sized that too much pruning by microglia through this mech­a­nism could con­tribute to synapse loss and neu­rode­vel­op­mental dis­or­ders such as autism and schiz­o­phrenia,” Stevens said. As it turned out, her lab’s find­ings sug­gested as much—that the normal pruning that takes place in chil­dren is somehow reac­ti­vated to drive synapse loss in the adult brain in dis­eases like autism, that impaired microglial func­tion may play a role in causing them.

President Aoun asked Stevens a number of questions, including one about the challenges facing women in the STEM fields.

Pres­i­dent Aoun asked Stevens a number of ques­tions, including one about the chal­lenges facing women in the STEM fields.

Awards, awards, awards

Stevens has received numerous awards for her ground­breaking work, including the Smith Family Award for Excel­lence in Bio­med­ical Research, a Dana Foun­da­tion Award, and an Ellison Med­ical Foun­da­tion New Scholar in Aging Award. Last year, she was one of 24 people in the world to be named a MacArthur Fellow, which includes a five-​​year, $625,000 “genius grant.”

Stevens noted that the genius grant would allow her to expand her lab’s focus. “The MacArthur award has been cat­alytic in the sense that it’s now enabling us to tackle really tough ques­tions that I may not have thought I could do before,” she said. “It also gave me the con­fi­dence to say ‘we’re just going to go for it.’ We’re going after some pretty hard ques­tions, but I’m excited about it and we’ll see where it goes.”

Time for questions

Stevens spent more than half of the hour­long event answering ques­tions from the audi­ence in the room, social media, and Aoun him­self, who asked Stevens to name some of the biggest chal­lenges facing women looking to excel in the STEM fields. She sug­gested that more must be done to help women com­plete lengthy doc­toral pro­grams, par­tic­u­larly those who are jug­gling their career with raising chil­dren. “Having chil­dren when you’re a post-​​doc is very expen­sive and I don’t think the system is in place to sup­port that,” she said. “We lose some very tal­ented women at that stage.”

One stu­dent in the audi­ence asked for advice on jump­starting his STEM career. “If you’re excited about a career in sci­ence now, take advan­tage of as many oppor­tu­ni­ties as North­eastern can give you,” she said. “You can’t just sit back and hope something’s going to happen. You actu­ally have to make it happen.”

Stevens, BPH’93, is a prime example. As an under­grad­uate in Northeastern’s med­ical lab­o­ra­tory sci­ence pro­gram, she did three co-​​ops in three dif­ferent clin­ical labs, including one at the Sahlgrenska Uni­ver­sity Hos­pital in Sweden. “All of these expe­ri­ences when you’re 20 years old, they can change your life,” she said last year, after win­ning the genius award. “It opened my eyes to what was out there.”

Fun year­book photo

At the end of the Q-​​and-​​A, Aoun gifted Stevens a framed year­book photo of her­self from 1988, her first year at North­eastern. “I had ‘80s hair,” Stevens said, elic­iting laughter from the crowd. “I haven’t seen this pic­ture in a long time. Thank you so much, this is really awesome.”

Photo by Adam Glanzman/Northeastern University

A photo of Stevens from 1988.