From Birdsong to Breakthroughs: How Songbirds Teach Us Brain Science

At Columbia University’s Zuckerman Mind, Brain, and Behavior Institute, Dr. Vikram Gadagkar, Assistant Professor of Neuroscience, leads a research project that investigates how brains learn from experience by producing and evaluating existing and new behaviors. Using zebra finches as a model system, his lab studies the neural mechanisms of trial-and-error learning, a process that underpins how both animals and humans acquire complex motor skills like speech or music.

Dr. Gadagkar’s fascination with the brain began early in life. As a child growing up in India, he was captivated by questions about behavior—especially what happens in animals’ brains when they learn something new. This budding curiosity crystallized when he attended a talk by renowned Indian American neuroscientist V. S. Ramachandran, whose pioneering work on phantom limbs demonstrated how sensations could persist in the brain even after a limb was lost. “I was completely blown away,” Dr. Gadagkar recalls. “I decided that I was going to grow up and be a neuroscientist.”

Despite his early dream of pursuing neuroscience, Dr. Gadagkar’s academic path initially led him elsewhere. Drawn to the rigor of quantitative science, he studied physics, chemistry, and mathematics as an undergraduate, and then went on to earn a PhD in fundamental physics at Cornell University. He even worked with a professor who was exploring exotic states of matter, such as supersolids. However, he ultimately changed his mind about long-term plans. “At the end of my PhD, I realized that if I wanted to follow my childhood dream of doing neuroscience, then this was the time,” he says.

Now, as a neuroscientist, Dr. Gadagkar is deeply engaged in collaborating with his lab to uncover how the brain learns and improves. “We are interested in trying to figure out how the brain gets better with practice,” he explains. “We’re asking: How does the brain actually improve through trial and error?”

To answer this question, a central focus of Dr. Gadagkar’s work is dopamine, a neuromodulator that his lab has shown acts as a performance prediction error signal. In juvenile zebra finches learning to sing, dopamine levels increase when the bird produces a syllable that closely matches the memorized version of the father’s song, but dopamine levels decrease when the match is poor. “Dopamine provides an evaluation signal for song learning,” Dr. Gadagkar explains.

To capture this evaluation signal, Dr. Gadagkar and collaborators developed a powerful tool for studying learning by creating the first ever dopamine photometry system for birds. By introducing genetically encoded receptors that emit light in the presence of dopamine, Dr. Gadagkar and collaborators can continuously monitor birds’ neural activity during song practice—and garner detailed analysis and understanding of birds’ learning processes.

This research draws on connections with artificial intelligence (AI), particularly reinforcement learning (RL), which has become a cornerstone of modern AI. “Reinforcement learning and its variants have emerged as some of the most successful AI algorithms in recent years,” Dr. Gadagkar says. “But even in AI systems like AlphaGo, early stages of learning often rely on supervised input before RL can be developed effectively.” With this in mind, in biological systems, this raises an open question: Can reinforcement learning alone account for skill acquisition early in development?

“We showed that midbrain dopamine neurons provide a performance prediction error signal in adult zebra finches,” Dr. Gadagkar explains. “But predictions are needed before the brain can generate a reinforcement signal. So does the very young brain first need to learn the mapping between motor output and sensory feedback before it can even make a prediction?” His lab is now addressing this foundational question through longitudinal studies of juvenile learning.

Additionally, looking ahead, Dr. Gadagkar’s lab is expanding its focus to include social behavior and female zebra finches, who evaluate male song during courtship. “Most of neuroscience has focused on how the brain produces behavior,” Dr. Gadagkar says. “We know very little about how one brain evaluates the behavior of another.” By using female birds as a model of social evaluation, the lab hopes to illuminate how neural systems assess external actions—a topic relevant to social cognition.

Overall, Dr. Gadagkar is striving to answer longstanding questions about how we learn and evaluate the world around us. With the ultimate goal of improving lives, he and his team look forward to continuing their work developing a deeper understanding of the brain. “Our goal is to combine the advantages of the songbird courtship system with state-of-the-art computational, theoretical, and experimental approaches to discover how brains evaluate behaviors, both self-generated and the behaviors of others,” he says.

Envisioned by Dr. Jeannette M. Wing, Executive Vice President for Research, the “Researcher of the Month” series celebrates Columbia University researchers at all levels — students, postdocs, and faculty — by showcasing their scientific contributions, passion for their work, and personal stories.