Functional properties and organization of inspiratory neurons at the caudal and rostral boundaries of the pre-Botzinger Complex inspiratory center in newborn rat brainstem slices

The pre-Botzinger Complex (preBotC) inspiratory center remains active in a brainstem slice. Our previous study showed that the preBotC neurons can be studied with multiphoton/confocal Ca 2+ imaging in slices with identified surfaces. The present study used 500-700 mum slices with the preBotC exposed to caudal or rostral border (r+preBotC or c+preBotC slices, respectively) and 250 mum thin preBotC slices to study comparatively the structure-function relationship of caudal and rostral preBotC neurons. r+preBotC slices produced a sigh-like activity, whereas c+preBotC produced a eupnea-like activity. Multiphoton/confocal Ca2+ imaging of neurons located caudally in the r+preBotC slices revealed a reconfiguring network, with a significantly higher number of clustered inspiratory neurons (compared to the dispersed rostral neurons in the c+preBotC slices). No rostrocaudal difference in the number of inspiratory cells was found in the thin slices suggesting that the rostrally-located structures may provide a stronger drive to preBotC inspiratory neurons than the caudally-located structures.