This study investigates how natural individual differences in brain cell physiology relate to behavioral traits associated with addiction-like behaviors. Dr. Maria-Rios and collaborators used a well-established animal model that classifies rats as sign-trackers (STs) or goal-trackers (GTs) based on how they attribute motivational value to cues paired with a reward. They recorded electrical activity from medium spiny neurons (MSNs), the primary neuron type in the nucleus accumbens, a brain region essential for reward and motivation. The researchers found that ST rats, which are more prone to assigning incentive value to cues and are more susceptible to addiction-like relapse, exhibited lower intrinsic excitability in neurons from the nucleus accumbens core compared to GT rats. These findings suggest that innate differences in how individual neurons respond to inputs may underlie behavioral differences in incentive learning and vulnerability to addiction. This mechanistic insight helps explain why some individuals may be more prone to addictive behaviors than others and could inform more targeted strategies for prevention and treatment.