Systems neuroscience research at Carnegie Mellon is centered on understanding how the diversity of discrete neural cell types in the cerebral cortex and basal ganglia give rise to perception and behavior. Different types of neurons distinguished by patterns of gene expression and anatomical properties interact in stereotyped and hierarchical ways in order to generate complex behavior. New findings and sophisticated molecular tools for the identification, monitoring, and control of neural activity in defined neural subtypes are revealing highly structured principles for information processing in the mammalian brain. Investigators use high-throughput methods to record neural firing, analyze cellular anatomy, and characterize gene expression. In doing so, they are identifying specific computational properties carried out by molecularly-defined groups of neurons, as well as making discoveries about how they are changed by experience and disease. These findings are relevant not only to identifying new disease treatments, but also in the design and optimization of engineered networks for artificial intelligence and neural prosthetics.