48 THE SCIENTIST | the-scientist.com
PROFILEJILL RIEMERA
s rodents scuttle through a maze, scientists can observe
the activity of their brains’ “inner GPS,” neurons that
manage spatial orientation and navigation. This posi-
tioning system was revealed through two different discoveries,
decades apart. In 1971, neuroscientist John O’Keefe found place
cells, neurons that are consistently activated when rats are in a
specific location, while observing the animals as they ran around
an enclosure. More than thirty years later, neuroscientists May-
Britt and Edvard Moser used a similar method to identify grid
cells, neurons that fire at regular intervals as animals move,
enabling them to keep track of navigational cues.
It was the early 2010s when neuroscientist Elizabeth Buffalo
and her team at Emory University’s Yerkes National Primate
Research Center in Atlanta started investigating what the brain’s
GPS looks like in primates. While conducting memory tests by
tracking the eye movements of primates viewing either familiar
or unfamiliar images, the researchers began to wonder: Was this
system also active in stationary animals? “They were moving their
eyes as they were forming a memory of these pictures,” Buffalo
says. “So we thought that maybe this eye movement exploration
was something that primates do in an analogous way to how
rodents explore as they move around a physical environment.”
One of Buffalo’s graduate students, Nathaniel Killian, put
this hypothesis to the test. Working with monkeys, he placed
electrodes into the entorhinal cortex—the brain region where grid
cells are found in rodents—and recorded brain activity while the
animals viewed images on a screen. One da y, Killian came into a
lab meeting with an announcement: he had found grid cells in the
primate brain (Nature, 491:761–64, 2012). Although it took many
more months to complete additional experiments to validate the
results, Buffalo remembers thinking during that meeting, “ Wow,
we’re seeing something really n e w.”FROM THE BASEMENT TO THE LAB BENCH
Buffalo conducted her first scientific experiment as a teenager in
Little Rock, Arkansas. Encouraged by her high school science
teacher, she embarked on an ambitious science fair project, which
involved investigating the behavioral effects of a chemical called
para-chlorophenylalanine (PCPA) on rats. Inspired by a TV news
segment noting that extreme risk takers had increased aggressiveness
associated with higher-than-average levels of PCPA, Buffalo decided
to put the behavioral effects of the chemical to the test.
To carry out the experiment, Buffalo set up a makeshift lab in
the basement of her house. Her science teacher helped her gatherthe necessary materials and expertise by connecting her with a
professor at the nearby University of Arkansas Medical School.
That professor provided guidance for her project and got her in
touch with the Arkansas-based National Center for Toxicological
Research, which donated rats for her experiment. Buffalo housed
the rodents in cages with water bottles provided by the university.
She injected the animals with different concentrations of PCPA,
then examined changes in aggression levels by administering a
small electric foot shock and documenting how much of a small
wooden rod the animals would chew away in response. As she’d
hypothesized, higher doses of PCPA made the rodents more
aggressive. “It ended up being a pretty involved project,” Buffalo
recalls. “A t one point, we had 20 rats in the basement.”The experience solidified Buffalo’s interest in science and
jumpstarted a series of summer jobs doing research. Most of those
were spent in a behavioral toxicology lab led by Merle Paule at
the National Center for Toxicological Research. Buffalo spent
several summers during high school and college in Paule’s lab,
working on experiments involving monkeys—such as assessing
the behavioral effects of caffeine and other drugs on the animals.
She coauthored a handful of papers about their research.
Although Buffalo maintained an interest in science, she
majored in philosophy at Wellesley College, where she started her
undergraduate studies in 1988. She traces this decision back to a
book, Scientific Realism and the Plasticity of Mind, by Canadian
philosopher Paul Churchland, which she’d read while doing research
for her high school science fair project. “I probably didn’t understand
half of it, but it just was super interesting,” Buffalo says.
Although science wasn’t her major, the subject remained
a dominant force in Buffalo’s life. Intrigued by the brain, she
concentrated her studies on the philosophy of mind, choosing
psychobiology, which dealt with the biological basis of
psychological processes, as her minor. Buffalo’s first neuroscienceStudying nonhuman primates, University of Washington neuroscientist Elizabeth Buffalo has identified
important features of the neural underpinnings of learning and memory.BY DIANA KWONUnravelling Memory’s Mysteries
I had these moments through almost every
class where I thought, gosh, the most
exciting thing I could ever try to figure out
is exactly what happens in the brain when
we learn something.
—Elizabeth Buffalo, University of Washington