Millions of children take Ritalin (methylphenidate hydrochloride) to treat attention deficit hyperactivity disorder, but the mechanism underlying the drug’s improvement of ADHD symptoms has been uncertain. Now, University of California, San Francisco, neuroscientists Antonello Bonci and Patricia H. Janak and their colleagues have filled in some of the details (Nat. Neurosci., DOI: 10.1038/nn.2506). The team dosed rats with Ritalin to study the drug’s effect on the amygdala, a region of the brain central to learning and emotional memory. The researchers found that Ritalin activates the D2 type of dopamine receptor on neurons in the amygdala and that this interaction is responsible for the drug’s ability to improve focus on a given task. They also discovered that the compound increases the speed of learning and does so by activating the D1 type of dopamine receptor. “Since we now know that Ritalin improves behavior through two specific types of neurotransmitter receptors, the finding could help in the development of better targeted drugs, with fewer side effects, to increase focus and learning,” Bonci says.