title: Nonlinear dynamics of respiratory patterns during maturation.
abstract: OBJECTIVE
  In this paper, we quantify the fractal scaling characteristics of phrenic neurograms during eupnea in piglets, the output of the respiratory neural network that accompany maturation We also attempt to investigate whether the fractal properties are altered with maturation.
  
  
  METHODS
  The phrenic neurogram in piglets was recorded from the C5 phrenic nerve during eupnea at four postnatal ages; the 3-6 days, the 7-14 days, 15-21 days and the 26-31 days age groups and analyzed using the maximum likelihood estimator (MLE).
  
  
  RESULTS
  Our results suggest that the mean fractal measures over a recording of five consecutive breaths during eupnea for each piglet in each group were higher during the first 6 days and slightly decreased for the 7-14 days and significantly decreased for the 15-21 days and significantly increased for subsequent maturation (the 26-31 days old group).
  
  
  CONCLUSIONS
  We suggest that there is a significant alteration in the fractal organization in piglet respiratory patterns during maturation and a decrease in the fractal value is unique to the 15-21 days old group.
authors.affiliation: Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA. Metin.Akay@Dartmouth.Edu
authors.forename: M
authors.initials: M
authors.lastname: Akay
authors.forename: M
authors.initials: M
authors.lastname: Sekine
authors.forename: K L
authors.initials: KL
authors.lastname: Moodie
mesh_terms: D000367:Age Factors; D000818:Animals; D005260:Female; D017709:Fractals; D008297:Male; D008962:Models, Theoretical; D016571:Neural Networks, Computer; D017711:Nonlinear Dynamics; D012137:Respiratory System / Q000254:growth & development*; D012815:Signal Processing, Computer-Assisted; D013057:Spectrum Analysis; D013552:Swine