In-vivo optogenetic identification and electrophysiology of glycinergic neurons in pre-Botzinger complex of mice

Breathing requires distinct patterns of neuronal activity in the brainstem. The most critical part of the neuronal network responsible for respiratory rhythm generation is the preBo center dot tzinger Complex (preBo center dot tC), located in the ventrolateral medulla. This area contains both rhythmogenic glutamatergic neurons and also a high number of inhibitory neurons. Here, we aimed to analyze the activity of glycinergic neurons in the preBo center dot tC in anesthetized mice. To identify inhibitory neurons, we used a transgenic mouse line that allows expression of Channelrho-dopsin 2 in glycinergic neurons. Using juxtacellular recordings and optogenetic activation via a single recording electrode, we were able to identify neurons as inhibitory and define their activity pattern in relation to the breathing rhythm. We could show that the activity pattern of glycinergic respiratory neurons in the preBo center dot tC was heterogeneous. Interestingly, only a minority of the identified glycinergic neurons showed a clear phase-locked activity pattern in every respiratory cycle. Taken together, we could show that neuron identification is possible by a combination of juxtacellular recordings and optogenetic activation via a single recording electrode.

Automated summary

The preBo·tzinger Complex (preBo·tC) in the brainstem plays a critical role in generating respiratory rhythm. This study aimed to investigate the activity of inhibitory glycinergic neurons in the preBo·tC of anesthetized mice. Using juxtacellular recordings and optogenetic activation, the researchers were able to identify and characterize the activity pattern of these inhibitory neurons in relation to the breathing rhythm.