Spontaneous Fluctuations of Human Pupil Reflect Central Autonomic Rhythms

Abstract:

Aim of this study is to assess whether and to what extent LF and HF rhythms contribute to spontaneous pupil diameter fluctuations at rest and during sympathetic activation by Head-Up Tilt Test 70°. ECG, Finapres and Respiration data from 10 normal subjects were recorded simultaneously to spontaneous pupil diameter fluctuations (SPDF). The respiratory rhythm and the LF component were clearly detected in all the SPDF series. The cross-spectrum analysis gave significant results (>0.5) in HF band. During tilt, a reduction in the total variability with a relative increase of the LF component was observed in HR, BP and SPDF signals. The multivariate analysis of the SPDF and of the cardiovascular variability series allows new insights into the physiology of pupil neural control. The effect of tilting on SPDF spectra and the physiological background of the pupil control are consistent with the hypothesis that pupil fluctuations reflect a generalized increase of the sympathetic tone.

Keywords:

Pupil Diameter Fluctuations - Autonomic Nervous System - Spectral Analysis

• REFERENCES

• 1 Usui S, Stark LW. A model for non-linear stochastic behaviour of the pupil. Biological Cybernetics 1982; 45: 13-21.
• 2 Otshuka K, Asakyra K, Kawasaki H, Sawa M. Respiratory fluctuations of the human pupil. Exp Brain Res 1988; 71: 215-7.
• 3 Yoshida H, Yana K, Okuyama F, Takashi T. Time-varying properties of respiratory fluctuations in pupil diameter of human eyes. Method Inform Med 1994; 33: 46-8.
• 4 Yoshida H, Miuta H, Gouhara T, Suzuki Y, Yana K, Okuyama F. Statistical properties of simultaneously recorded fluctuations in pupil diameter and heart rate. Proc IEEEEMBS Conf. 1995
• 5 Task Force, Heart Rate Variability.. Standard of measurement, physiological interpretation and clinical use. Circulation 1996; 93: 1043-65.
• 6 Chaudhuri BB, Kundu P. Optimum circular fit to weighted data in multi dimensional space. Pattern Recog Letter 1993; 14: 1-6.
• 7 Kay SM, Marple SL. Spectrum analysis: a modern perspective. Proc IEEE 1981; 69 (Suppl. 11) 1380-414.
• 8 Calcagnini G, Miraglia F, Censi F, Lino S, Calcagnini G, Cerutti S. Cardiovascular autonomic rhythms in spontaneous pupil diameter fluctuation. IEEE Computers in Cardiology Proc . 1997: 211-4.
• 9 Murata A, Iwase H. Evaluation of mental workload by fluctuation analysis of pupil area. IEEE/EMBS Conf Proc. 1998: 3094-7.
• 10 Cohen M. Neurogenesis of respiratory rhythm in the mammal. Physiol Rev 1979; 59: 1105-73.
• 11 Borgdoff P. Respiratory fluctuations in pupil size. Am J Physiol 1975; 228 (Suppl. 04) 1094-102.