Neurogliaform cells dynamically decouple neuronal synchrony between brain areas

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.

Automated summary

Effective communication across brain areas requires distributed neuronal networks to synchronize or decouple their activity. GABAergic interneurons not only lock the ensembles to oscillations, but also synchronize the firing of pyramidal cells with cortical inputs without reducing their activity. The temporary disengagement of synchrony allows for new communication partners.