BOSTON—Carnegie Mellon University chemists have solved a decade-long molecular mystery that could eventually help scientists develop drug therapies to treat a variety of disorders, including epilepsy and Alzheimer’s disease. Using intensive theoretical and computational calculations, Carnegie Mellon researchers have modeled the initial molecular changes that occur when the neurotransmitter glutamate docks with a receptor on a neuron, which sets in motion a chain of events that culminates in the neuron firing an electrical impulse.