Many of the critical functions of the brain--cognition, perception, decision making, etc.--are performed by the cortex. The cortex is made up of interconnected networks containing many different classes of excitatory and inhibitory neurons, whose roles in both normal brain activity and disease are poorly understood. Each neuron contributes to activity in the surrounding local network and receives a constant barrage of network synaptic input in return. The Cardin lab investigates this dynamic and bidirectional relationship between neuron and network at multiple levels, including cellular and synaptic mechanisms, circuit interactions, and behavior. Our main focus is the different roles of distinct types of GABAergic interneurons in regulating network activity, and how those roles change with sensory context, behavioral state, and disease.