A CHAOTIC SYSTEMS-ANALYSIS OF THE NASAL CYCLE

The nasal cycle is a chaotic ultradian rhythm with a period ranging fr om about 75 to 200 minutes. It has been shown to correlate highly with EEG amplitude in the contralateral hemisphere at virtually all freque ncies, suggesting a connection between this rhythm and laterality of b rain function. During a three-week period, five participants estimated airflow from both nostrils every 30 minutes during waking hours. Esti mates were recorded on Likert scales and analyzed in three distinct ph ases: (1) reconstructing two-dimensional attractors by lagging and emb edding; (2) computing Fourier frequency analyses; and (3) estimating f ractal dimensions. Attractor reconstructions demonstrate noticeable or der when compared to Monte Carlo reconstructions of the same data sets , and dimension estimates are in the fractal range. The attractor reco nstruction, in combination with the frequency analyses, show distinct individual differences in the structure of the nasal cycle. The advant ages of chaotic systems analyses over traditional behavioral statistic s are discussed.