Fig. 6.

Examples of peak-interval maps in 3 preparations. The amplitude of each burst (y-axis) was plotted against the period to the following burst (x-axis). A: example of a postmetamorphic preparation. All the recordings performed in postmetamorphic animals exhibited nonlinear chaos-like complexity. B: example of a premetamorphic preparation. No nonliearities were detected in the signals at both pH. C: example of a premetamorphic preparation of which the dynamics of ventilatory output became nonlinear and chaos-like at low pH.