Figure 3.

Characteristic profiles of extracellularly recorded neuronal population activity and examples of perturbations of inspiratory motor output activity and blood pressure produced by pharmacological excitation of neurons within the pre-BötC or BötC regions in the adult rat in vivo. A, A typical example of pre-inspiratory/inspiratory (pre-I/I) population activity used for the identification of pre-BötC. B, An example of post-I and aug-E population activity (post-I/aug-E, simultaneously recorded in this example) used for the identification of BötC. In both A and B, the raw recording from the phrenic nerve (PN) and PN integrated activity (∫PN) are shown at the bottom. C, A 500 ms duration microinjection of L-Glu (Glutamate) in the pre-BötC produced an increase in the ∫PN burst frequency (see the trace for integrated PN activity, ∫PN), and a transient decrease in the ABP. The respiratory frequency (f_R; bottom trace, green) increased primarily due to reduction in expiratory phase duration (T_E trace, blue) at a relatively unchanged inspiratory duration (T_I trace, red). D, A microinjection of L-Glu in the BötC caused a rapid suppression of PN activity (see traces for ∫PN and inspiratory, T_I, and expiratory, T_E, durations) accompanied by an increase of ABP. In Cand D, L-Glu (10 mm, 5 nl) was microinjected bilaterally during the brief (500 ms) pulse; the moments of injections are indicated by brown arrows. Traces for T_I, T_E, and f_R, represent corresponding running time intervals of these parameters before, during, and recovery from L-Glu microinjection.