Dynamics of early and late phases of the phrenic neurogram during maturation

We investigate the dynamics of early and late phases of the phrenic neurogram during maturation. We have used using the matching pursuit (MP) method to examine the effects of maturation on breathing patterns in both time and frequency domains. The phrenic neurogram in piglets was recorded from 9 piglets during eupnea (normal breathing) at three postnatal age groups; 3-6 days (n=3), 15-21 days (n=3) and the 25-31 days (n=3). During the first 6 days of postnatal age, the long horizontal structured components representing the continuous respiratory activity, and circular structured components, representing the burst type breathing activities, were at both the early and late phases of the phrenic neurogram. The early phase of phrenic activities is largely composed of continuous neural activity. However as maturation proceeds, but both the continuous and burst type neural activities were present during the late phase of the phrenic neurogram.