Functional flexibility in cortical circuits.

Cortical networks receive a highly variable stream of inputs from internal and external influences, and must flexibly adapt their operations on a short timescale. Recent work has highlighted this state-dependent functional flexibility of cortical circuits and provided initial insights into underlying circuit-level mechanisms. Transitions from quiescent to aroused or task-engaged behavioral states are associated with common motifs of network activity, including changes in correlations and enhanced sensory encoding. Evidence points to a key role for selective activation of specific GABAergic interneuron populations in mediating mode-switching in cortical networks. Finally, inhibitory interneurons may function as a critical target for convergent state-dependent neuromodulatory sculpting of cortical circuits.