Damage to the prefrontal cortex, a part of the frontal lobes, can result in poor planning, unreasonable risk taking, and inappropriate social behaviour. The prefrontal cortex thus plays a crucial role in the decision making and emotional regulation that allow us, as humans, to function smoothly in our personal lives. The lives of rats are arguably simpler than our own, but they must solve many of the same everyday tasks as humans: deciding whom to fight and whom to befriend, knowing when to react in anger and when to appease, deciding when to keep searching (e.g., for food) or when to stay with what you have. Rats, too, have a prefrontal cortex which, anatomically, looks a lot like parts of the human prefrontal cortex and may serve a similar purpose. The functioning of this region in the rat’s brain is the focus of David Euston’s research. By looking at the activity of individual brain cells during complex decision-making tasks, he hopes to uncover how the prefrontal cortex integrates sensory input, memory, and emotional state to guide the rat in adaptive behaviour. Because many brain structures, including parts of the prefrontal cortex, are conserved across species, uncovering the computations served by the rat prefrontal cortex will hopefully shed light on the functioning of our own prefrontal cortex.