Mechanisms Underlying Adaptation of Respiratory Network Activity to Modulatory Stimuli in the Mouse Embryo

Figure 3

Detection of pacemaker neurons in the embryonic respiratory network. (a) Top: schematic of an embryonic transverse brainstem slice used for extracellular electrode recording from the isolated preBötC network on one side and calcium imaging of the contralateral preBötC network. The fluorescent image is an example where 32 preBötC cells expressed calcium transients simultaneously and in phase with the whole network. Bottom: simultaneous recordings of network electrophysiological activity (Int preBötC, top) and calcium transients (Δ/) in individual cells numbered 1–32 from top to bottom. All selected cells displayed fluorescent changes in phase with inspiratory bursts monitored at the network level. (b) Same recordings after blockade of chemical synapses within the network by exposure to a cocktail of 20 μM CNQX, 10 μM AP5, 10 μM bicuculline, and 1 μM strychnine. The majority of cells fell inactive (black traces), but a few neurons remained capable of generating spontaneous rhythmic fluorescent changes (red traces). These cells were thus identified as preBötC pacemaker neurons.

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