PREBOTZINGER COMPLEX AND PACEMAKER NEURONS - HYPOTHESIZED SITE AND KERNEL FOR RESPIRATORY RHYTHM GENERATION

Identification of the sites and mechanisms underlying the generation o f respiratory rhythm is of longstanding interest to physiologists and neurobiologists. Recently, with the development of novel experimental preparations, especially in vitro en bloc and slice preparations of ro dent brainstem, progress has been made. In particular, a site in the v entrolateral medulla, the preBotzinger Complex, is hypothesized to con tain neuronal circuits generating respiratory rhythm. Lesions or disru ption of synaptic transmission within the preBotzinger Complex, either in vivo or in vitro, can abolish respiratory activity. Furthermore, t he persistence of respiratory rhythm following interference with posts ynaptic inhibition and the subsequent discovery of neurons with endoge nous bursting properties within the preBotzinger Complex have led to t he hypothesis that rhythmogenesis results from synchronized activity o f pacemaker or group-pacemaker neurons.