Neuroscientist at the Salk Institute for Biological Studies

What would you say to aspiring scientists? 
“You’ve really got to be your biggest cheerleader. Getting rejected is always going to suck, but it gets easier. You begin to understand what the lessons were from being rejected.”

Dr. Christian Cazares’ scientific journey began, of all places, with a trip to the principal’s office. His intention had been to dazzle his second-grade classmates with a trick he’d learned from his dad: if you put baking soda and vinegar in a plastic bag, the ensuing chemical reaction will cause the bag to inflate and eventually burst. Laughing, Christian recalls, “The teacher saw me with a Ziploc bag full of white powder and a little vial of vinegar. My parents got called in, and they had to explain what I [was doing].”

Once in high school, Christian’s burgeoning interest in chemistry and experimentation converged with content from his AP Psychology class. Through this course, he learned about chemical neurotransmitters like dopamine and serotonin that regulate brain function. He also became enamored with the study of human cognition, intrigued by the many factors that shape why and how humans behave the way we do. With this motivation, Christian chose to pursue his undergraduate studies at UC Berkeley as a chemistry major, with a particular focus on the biochemistry of the brain.

After this first semester, Christian chose to drop his chemistry major. But although he describes this difficult moment as a kind of identity crisis, it also reveals what has since become a prevalent theme in his scientific journey: a constant willingness to stop, reflect, and interrogate his own passions and goals.

Before long, Christian found a better home for his interests in Berkeley’s cognitive science major — a relatively new area of study that unites perspectives on human cognition from different disciplines, such as psychology, neuroscience, philosophy, and computer science. “I’m glad I got that breadth in looking at human behavior,” Christian notes. “It made me very open-minded about what I would eventually do as a researcher.”

Moreover, it was through this major — during a class on neuropsychology taught by Dr. Richard Ivry — that Christian first remembers feeling capable of a career in science. As part of exams, students in this course were asked to design novel experiments that could identify the likely neurobiological source of a hypothetical patient’s cognitive impairments. “I enjoyed the freedom that [the question] came with,” he explains. “It wasn’t just me sitting in a classroom and absorbing information. I had to think about a problem and about all the possible interpretations of my results. I remember feeling like I could be a scientist.”

After this class, Christian began as a research assistant in the Ivry Lab, where he conducted experiments on how humans plan and inhibit motor actions — functions that are critical to how we navigate the world. For example, when a driver waiting at an intersection sees the traffic light turn green, how do they efficiently initiate the movement of pressing the gas pedal? And how can that planned movement be prevented if a pedestrian suddenly jumps into the street?

Although Christian enjoyed these early research experiences, as his graduation approached he took time once again to pause and reevaluate his research interests and goals. Working with humans satisfied his goal of studying complex cognitive processes — but it did not allow him to peer deep inside the brain, to observe its activity directly and understand “the nitty gritty chemicals,” like dopamine and serotonin, that control it.

So, after graduating from Berkeley, Christian applied to another NIH-funded program called PennPrep, which allowed him to spend the next two years pursuing new research opportunities. He took full advantage of the exploration this program allowed, seeking training in two labs: first the lab of Dr. Irwin Lucki, and then that of Dr. Brian Litt. These training experiences expanded the set of scientific skills Christian had built thus far by giving him the chance both to deepen his comfort with complex data analysis techniques and to probe neural function in animals.

In the fall of 2016, Christian began his PhD in neuroscience at UC San Diego, where he was supervised by Dr. Tina Gremmel. In his research, Christian examined how goal-directed behavior — such as seeking out valuable materials like food or money  — is disrupted by alcohol dependence. He found that dependence on alcohol reduced an animal’s ability to make decisions that led to food rewards, while also impairing activity in brain regions thought to support adaptive decision-making.

Christian’s willingness to be deliberate about what he would research and where he would do it helped ensure that he had a chiefly positive experience in graduate school. As he pondered what path to take next, however, uncertainty leaked in — spurred on by the unrest of the COVID-19 pandemic. In particular, Christian remembers feeling uncharacteristically cynical about the value of staying in academia after his PhD. “I was very, very sad during COVID — alongside many people. Especially during a lot of the social unrest that coincided with it,” he says. “It seemed like the world just wasn’t going in the right direction. Everyone was looking out for themselves. So I thought, I’m just going to get the highest paying job I can find. I’m going to protect myself with money and play the game the world wants me to play.”

As time went on, and Christian gave himself more time to reflect, he found that his mentality began to reframe. While he remains concerned with the direction of modern society, he found himself returning to the reason he pursued science to begin with. “I started to think, what is my time here on Earth for, if not to enjoy that time in a way I find meaningful?”

Beyond the content of Christian’s research itself, one of the major factors in his decision to remain in academia was the opportunities it provides for mentoring younger generations of scientists. While at UC San Diego, Christian, Maribel, and several other graduate students spearheaded the creation of a mentorship organization called Colors of the Brain, aimed at providing guidance and mentorship to undergraduates from historically underrepresented backgrounds who are interested in neuroscience.

When reflecting on advice he has for aspiring scientists, Christian emphasizes the value of seeking out and applying to every program, grant, or fellowship one is eligible for. To help with this goal, he heralds the value of social media platforms for promoting information about research-related opportunities. “Twitter is an excellent resource. I tell undergrads to follow institutions, follow programs, follow conferences. People are very free with advice, resources, and applications, which might otherwise be locked behind an email list that you didn’t know you could sign up for.”

Currently, Christian is getting acclimated to life as a postdoctoral scientist in the Salk Institute for Biological Sciences, where he now works with Dr. Kay Tye. Here, he has continued his remarkable funding record as an NIH D-SPAN scholar, a prestigious award that supports scientists during their transition from PhD to postdoctoral research. His work now will continue to investigate the neural mechanisms of complex decision-making. He aims in particular to investigate the phenomenon of social competition — such as that which occurs when animals must compete against peers for food in environments where resources are scarce. Continuing his long-held fascination with neurotransmitters, Christian hopes in particular to understand how serotonin shapes how dominant animals act in this kind of situation.

Christian’s path through science thus far underscores the value of continuous curiosity and self-exploration — of remaining in touch with your goals, priorities, and aspirations as they evolve. All the while, he has demonstrated a resilient commitment to seeking out opportunities for career advancement and growth, while also emphasizing the importance of sharing them with others. In doing so, Christian will undoubtedly continue to encourage and empower budding scientists who might hope to follow in his footsteps.