Marino Pagan is a postdoctoral researcher in the laboratory of Carlos Brody at Princeton University. He conducted his undergraduate studies in Italy at Scuola Superiore Sant’Anna and at University of Pisa, where he received his B.S. in computer engineering in 2006 and his M.S. in control engineering in 2009. He received his Ph.D. in neuroscience from University of Pennsylvania in 2015 under the supervision of Nicole Rust. His current research focuses on understanding the neural mechanisms underlying context-dependent behavior. To approach this problem, he trains rats to perform complex tasks traditionally studied in primates, and he takes advantage of the rich experimental toolkit available in rodents. By combining state-of-the-art experimental and computational techniques, he ultimately aims to shed light on the neural substrates of flexible cognitive behavior.
“Neural mechanisms underlying flexible decision-making”
An identical sensory stimulus can provoke different responses depending on the context. For instance, imagine a cell phone ringing in another room. In this case, you would focus on the location of the phone. But if a phone rings on the subway, you might focus more on the sound of the ringtone to determine if it’s yours. This context-dependent interpretation of sensory information is central to decision-making. However, how the brain carries out this function is largely unknown. We have developed a new behavioral task that forces rats to make a different decision based on the context of an identical auditory stimulus. The rat hears a series of tones that vary in frequency (high or low) and location (left or right). In one task, the rat is rewarded for orienting toward the location with the greatest number of tones. In another task, the rat is rewarded for orienting in a specific direction if the total number of low-frequency tones was higher than the total number of high-frequency tones. For each task, the reward is dependent on the context, even though the sensory stimuli are the same. We can then observe moment-to-moment neural activity to determine how context and flexible decision-making occur in the brain. We hypothesize that a few regions in the rat’s brain are crucial for the process: the frontal orienting fields, or FOF; the medial prefrontal cortex, or mPFC; and the striatum. We will use sophisticated genetic and pharmacological techniques to manipulate these brain areas and observe how they affect task performance. Because of the highly controlled nature of this novel task, we can also develop powerful statistical models to link brain activity to behavior. This combination will offer an unprecedented opportunity to unravel how the brain makes complex decisions in a changing environment.