Intrinsic periodicity of the pontile pneumotaxic mechanism.

Abstract

Microelectrode explorations in the region of the pneumotaxic center (dorsolateral rostral pons) have revealed the presence of numerous neurons discharging synchronously with respiration. To determine whether these discharges are intrinsic in origin or are activated by impulses from other regions, half of the pons was isolated by means of sectioning procedures, and the isolated region was explored for periodic discharges with microelectrodes. In preparations where hemisections were made but connections across the mid-line were left intact, discharges synchronous with respiration were found. In addition, two types of periodic discharge not synchronous with respiration were found; however, there is no conclusive evidence which relates these discharges to respiration. In the completely isolated hemi-pons (hemisection plus sagittal section), no definitely periodic discharges were found. It is therefore concluded that the periodic respiratory discharges in the pneumotaxic center are probably not intrinsic in origin, but are dependent on connections with other regions of the brain stem.