Effective communication across brain areas requires distributed neuronal networks to dynamically synchronize or decouple their ongoing activity. GABAergic interneurons lock ensembles to network oscillations, but there remain questions regarding how synchrony is actively disengaged to allow for new communication partners. We recorded the activity of identified interneurons in the CA1 hippocampus of awake mice. Neurogliaform cells (NGFCs)—which provide GABAergic inhibition to distal dendrites of pyramidal cells—strongly coupled their firing to those gamma oscillations synchronizing local networks with cortical inputs. Rather than strengthening such synchrony, action potentials of NGFCs decoupled pyramidal cell activity from cortical gamma oscillations but did not reduce their firing nor affect local oscillations. Thus, NGFCs regulate information transfer by temporarily disengaging the synchrony without decreasing the activity of communicating networks. To generate adaptive behavior, our brains constantly combine information from multiple sources. How do neuronal circuits orchestrate and maintain the balance of different input streams in the face of constant change? Sakalar et al. discovered that neurogliaform cells were strongly coupled with gamma oscillations that are associated with gating the interaction of hippocampus and cortex (see the Perspective by Craig and Witton). The activity of neurogliaform cells was correlated with a decrease in coupling between pyramidal cell firing and gamma oscillations without affecting the overall levels of activity of the pyramidal cells. Neurogliaform cells locally released the neurotransmitter γ-aminobutyric acid, which selectively decreased the influence of neocortical inputs to hippocampal area CA1 at specific stages in the local field potential. This modulation of inputs allows for the transfer of different types of information at different times. —PRS Input selection in brain neuronal networks involves a local inhibitory cell that can decouple neuronal synchrony selectively and temporarily.
