University of Pittsburgh


In a world that faces increasingly complex challenges, some students choose to devote years of their lives to unearthing raw knowledge, the fuel of discovery. Although the path of a PhD student isn't easy, it's a rite of passage that stimulates original thinking and novel solutions.

Written by Jennifer Bails



Sometimes, when Daniel Jimenez closes his eyes at night, a galaxy of star-like fluorescent green spots appears against the pitch-black screen of his mind. In the constellations of his dreams, each star contains an amorphous nub surrounded by branches of thin, dangling strings. The strings float, undulating in the darkness like ethereal sea creatures moved by invisible currents.

In the waking world, Jimenez—a 28-year-old graduate student—spends many of his days hunched over a fluorescence microscope studying the brain sections of mice. He’s well along the path to obtaining a PhD degree. Since arriving at Pitt in 2004, Jimenez has focused on understanding the properties and promise of neurons, specialized cells in the nervous system that dispatch all the activities of the mammalian brain.

Unlike other cells in the human body, most neurons don’t reproduce. Their number is finite. Yet in a few areas of the brain, new neurons are generated throughout life and integrate into existing networks. These rarer neurons, born anew in adults, are believed to hold answers for the future treatment of traumatic brain injuries and degenerative diseases. Ultimately, those answers are what Jimenez pursues, and the work is intense.

“I see neurons even in my sleep,” he admits.

In his dreams, each fluorescent core represents the control hub of a neuron. Its dangling strings look like dendrites. In the real world, these branch-like fibers receive electrochemical signals from other neurons and transmit them to the cell’s information-processing center. How the newborn neurons build these transmission connections and what factors control this process are of tremendous interest to scientists seeking to coax other parts of the brain to generate new cells as replacements for damaged or dying ones.

Jimenez is a sixth-year graduate student in the final months of completing his Pitt doctoral degree. Graduate students are experts-in-training: They are the ones crafting the keys to unlock new, raw knowledge. He is part of a legacy of learning passed down through the centuries to create a factory, of sorts, for producing knowledge-masters. Graduate education continues to be the world’s greatest hope for solving daunting challenges in medicine and health care, energy, climate change, poverty, public education, space exploration, and on and on.

A key component of a Pitt doctoral program—in any field—is the opportunity for students to look at problems creatively, from various vantage points, says James V. Maher, a Pitt professor of physics, who recently announced he is stepping down from his long-held role as provost and senior vice chancellor to return to the faculty. “You have to be able to study a problem, look for holes in the data, and wonder from where you might be able to draw a solution. It’s essentially a creative process.”

At the most fundamental level, doctoral education involves learning everything there is to know about a small part of the world—and then doing the original research necessary to deepen that understanding, says Patricia Beeson, Pitt’s vice provost for graduate and undergraduate studies. Increasingly, too, doctoral students must understand their own niches of expertise within a vastly complex world of evolving research, conducted by others worldwide. Each new piece of raw knowledge helps to solve the larger puzzle. “With PhD training, there is really no endpoint,” says Beeson, who also is a professor of economics and public policy. “It is all part of a continuum on the road to becoming an independent thinker and scholar.”

For Jimenez, that has meant literally years of his life devoted to advancing his own knowledge—observing brain cells through the lens of a microscope, reading the scientific literature on brain neuronal networks in the olfactory system, designing research projects to reveal new facets of information, analyzing computer data and figuring out how to interpret and communicate his findings, and writing grant proposals to fund his work.

Most of his time is spent in the University of Pittsburgh’s Center for Neuroscience and the Center for the Neural Basis of Cognition, a joint venture between Pitt and Carnegie Mellon University.

Now, with graduation approaching, he can safely say he is one of the world’s foremost experts on neuronal activity in the mouse olfactory bulb and, specifically, how such actions affect the integration and survival of newly generated neurons in that region of the brain. “It’s a weird thing to think I am one of about five people anywhere who know all about how this stuff works,” he says.

Across the nation, interest in PhD education is on the rise, according to a recent report by the National Science Foundation. In 2008, the Doctor of Philosophy degree was awarded to 48,802 U.S. students, an increase of 14.5 percent over the past decade.

Reflecting these national trends, the population of PhD students at Pitt also has grown in recent years, as have the students’ achievements. The number of PhDs bestowed by the University has risen by 30 percent since 1995 to more than 400 each year. This increase ranks Pitt 18th among public institutions and 29th among all universities nationwide in the number of PhDs it produces, according to the Center for Measuring University Performance. Pitt has a particularly stellar tradition of research excellence across many disciplines, which is part of what draws top students, like Daniel Jimenez, to the University from throughout the nation and the world.

Jimenez has been interested in science ever since he was a youngster growing up as a first-generation American born into a successful family of Cuban immigrants. His father, now an attorney, and nine siblings escaped to the United States just before the Cuban missile crisis, fleeing oppression in Havana under Fidel Castro. The siblings were placed in orphanages and foster homes across the country before finally being reunited in Miami in the late 1960s.

“I’m proud of my family,” says Jimenez, naming their professions as he points out his aunts, uncles, and cousins in a photograph from a family reunion. A doctor. Two lawyers. A firefighter. Several small-business owners. A veterinarian. An engineer. “When I get my PhD,” Jimenez says,  “that will be a first—even in a family where everyone is working really hard and doing their best.”

Jimenez set out to become an engineer, earning his bachelor’s degree in chemical engineering and biomedical engineering from Carnegie Mellon University in 2004. But during his undergraduate studies, he became fascinated with neuroscience and took advantage of the active collaborative ties between Pitt and its neighbor Carnegie Mellon. He began working in the laboratory of Pitt neurobiology professor Elias Aizenman, who studies cellular signaling pathways that lead to the death of neurons. “Neuroscience sits at this very creative intersection of biochemistry, genetics, physics, and many other disciplines,” Jimenez says. “I just fell in love with it.” Inspired by his research experiences in Aizenman’s lab, Jimenez applied to Pitt’s graduate program in neuroscience and enrolled immediately after completing his undergraduate education.

Making the transition from undergraduate school to unstructured graduate work isn’t always easy—and it isn’t for everyone, says Beeson. “You have to enjoy having extreme focus on one topic until you get your answer. Students who are really good at directed study can have a difficult time asking original questions and setting up their own course of study to answer those questions.”

Jimenez has thrived with this kind of intellectual freedom in Pitt’s neuroscience program, where years are spent doing independent research, which brings the joys of intellectual discovery and the anguish that occurs when students encounter inevitable hurdles. Overcoming those roadblocks requires persistence and a willingness to fail without taking failure personally—much like athletes seeking to excel at their sport, Beeson says. “Whenever you try to be the best at something, that’s painful,” she explains. “But with that pain comes this incredible feeling of satisfaction that you never knew you could actually know so much or do so much on your own.”

Jimenez recalls the frustration of long months when none of his experiments worked and his data weren’t making sense. “It seems to happen to everyone,” he says. “Somehow, with the help of your advisor, you get through it.” One of his principal PhD advisors is Nathaniel Urban (A&S ’91, ’96G, ’98G), who earned his own PhD in neuroscience from Pitt and also serves on the faculty here and at Carnegie Mellon. The mentor’s main role is to teach students how to ask original questions—and how to answer them—to advance their fields.

“A PhD gives you a certain mindset of thinking about things in a rigorous, data-driven, highly empirical way that is essential in so many other areas,” says Urban. “More and more careers today require a certain amount of technical sophistication. There’s a demand for people who can dive into a difficult area, where there’s not a great deal of understanding as to how things work, and figure it out. In some sense, that’s really what a PhD prepares you to do.”

The outcome that signifies mastery at the doctoral level is a dissertation, an in-depth research account that makes a novel contribution to an area of study and demonstrates mastery of scholarship in a particular discipline. In the humanities and social sciences, the dissertation usually serves as the foundation for a first book, whereas in science and engineering, it can comprise several technical articles published during the student’s graduate years. Ultimately, PhD students must defend their dissertations publicly before faculty committees that act as final juries in evaluating the work.

“The dissertation is the key component of doctoral training,” says Alan Sved, a Pitt professor of neuroscience and psychiatry. “It is developing a research project and seeing it through to completion,” adds Sved, who is chair of Pitt’s Department of Neuroscience. “Students must demonstrate that they know how to analyze the data they collect and that their findings are significant enough to be published.”

Still, everything a PhD candidate needs to know is not embodied in the dissertation alone. Doctoral students learn to become world-class researchers, but they also prepare for the demands of careers in academia and the world at large. This means developing the communications and management skills needed to run their own offices, mentorships, and laboratories—or, alternatively, to work in policymaking, industry, or other future-shaping careers. They learn from those who, before them, traveled across unexplored terrain to forge new paths of knowledge.

“It’s an apprenticeship model,” says Beeson, “and we still haven’t, after all of these hundreds of years, figured out a better way to transfer knowledge from one generation to the next.”

These days, a key aspect of this process is the ability to make leading-edge discoveries by collaborating with other smart people from various disciplines. And this is an area in which the University of Pittsburgh excels. In particular, Pitt has emerged as a leader in training young scientists, mainly by rethinking the very notion of what graduate studies can be. It has established new graduate programs that are based upon collaborations among multiple schools, including medicine, arts and sciences, and engineering.

More than half of Pitt PhD graduates obtain faculty positions at other colleges and universities, joining the ranks of those responsible for educating the next generations of university students and lifelong knowledge-seekers. The number and quality of these placements have increased in recent years—a sign that Pitt has clearly become a major player on the national stage vis-à-vis doctoral education. Many other PhDs receive postdoctoral fellowships, often the first step on a path toward key leadership positions in academia, government, industry, and entrepreneurial ventures.

The importance of doctoral education to the future of our society can hardly be overestimated, Beeson says. “We want to develop our PhD students as scholars in the fullest sense of the word—scholars who study, who learn, and who share what they learn in ways that benefit the broader community.”

During his years as a graduate student, Jimenez has worked to polish a range of skills. He is, for instance, working to promote diversity in neuroscience through an appointment to the professional development committee of the Society for Neuroscience. This year, he served as president of Pitt’s Graduate and Professional Student Assembly. He also organized science policy seminars at Pitt through his role on the Center for Neuroscience Outreach and Advocacy Committee. “Daniel understands that—for the scientific disciplines to survive—the public needs to know what we do and why it is important,” Sved says. “He is really energized to take up that cause.”

Beyond this whirl of activity, Jimenez remains keenly focused on his research, on the secrets still held by newborn neurons in the adult brain. Visions of fluorescent cells keep glowing in the dark, lighting the way ahead.