Neuroscience dogma had long dictated that the adult human brain did not create any new neurons.
The only time neuron numbers could increase was thought to be during fetal development and early childhood.
Their work has been so fruitful that it could provide them with a lifetime worth of projects.
But she and her collaborators can’t waste any time.
But Spalding persevered, and her hard work eventually paid off.
Last June, she published a paper in which she conclusively stated that adult human did indeed build new neurons in their brains.
They and their co-authors had solved one of neuroscience’s longstanding mysteries.“We found stem cells in the hippocampus of adult mice and rats that could create new neurons,” Gage says.It was groundbreaking work, but at the time not everyone was convinced of its importance.By 2050, Frisén and Spalding estimate, the bomb pulse will have completely dissipated.The premise of bomb pulse dating is fairly straightforward.Spalding and her postdoc advisor Jonas Frisén had a hunch that a pulse of radioactive carbon created by above-ground nuclear tests during the Cold War could help solve the riddle.“A geopolitical phenomenon—this Cold War bomb testing—has, in a way, put a date stamp on everything and everybody,” Spalding says.Standing outside the low, gray industrial building, she watched as horses went in one side and, about 15 minutes later, a worker appeared on the other end, holding a head, neurons and all.“It was precisely as revolting as it sounds,” she says.Spalding would then spend hours chipping away to extract the necessary cells, a grisly procedure that was just the first in a decade-long stretch of hurdles she had to surmount.“Had we known how difficult it was going to be, we never would have stuck with it,” says physicist Bruce Buchholz, one of Spalding’s co-authors and an expert on bomb pulse dating at the Lawrence Livermore National Laboratory outside San Francisco.