Figure 6.

Identification of nonrespiratory bursting neurons in PAm that are spatially near inspiratory neurons. Multiple unit activity was recorded in PAm (center trace) simultaneously with activity in the contralateral RA (bottom trace) and with air sac pressure (top trace). The arrow indicates the time of simultaneous bursting in RA and the nonrespiratory PAm unit. Also visible in the background of the PAm electrode are units that fire in phase with inspiration. The thick gray line is a rectified and smoothed version of the PAm trace after the burst spikes have been removed, highlighting the respiratory rhythm of this background activity. In this example, the respiratory cycle was longer when a burst occurred than when the PAm unit remained silent. Changes in respiratory cycle length were occasionally observed during bursts in PAm and/or RA; however, this phenomenon was not consistently seen. exp; Expiration; insp, inspiration.