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Accession Number:
ADA411212
Title:
Baroreceptor-Sensitive Fluctuations of Heart Rate and Pupil Diameter
Descriptive Note:
Corporate Author:
ISTITUTO SUPERIORE DI SANITA ROME (ITALY) LAB OF BIOMEDICAL ENGINEERING
Report Date:
2001-10-25
Pagination or Media Count:
5.0
Abstract:
It is generally known that the pupil is under the control of the autonomic nervous system. Recently, those rhythms charactering the autonomic fluctuations of heart period and arterial blood pressure have been detected in spontaneous Pupil Diameter PD fluctuations. The physiological mechanisms underlying such variability have not been widely investigated. Aim of this study was to investigate the origin of the pupil fluctuations in humans, using a non-invasive modulation of carotid baroreceptors by Neck Suction NS. To this purpose, we simultaneously recorded ECG, respiration activity, NS pressure and PD fluctuations from 10 normal subjects. The equipment for the PD measurement and the NS stimulation was developed in our laboratory. The response of the pupil to the NS was studied at stimulation frequencies of 0.10 and 0.20 Hz by using parametric spectral and cross-spectral estimation. In all subjects, the NS rhythms were clearly detectable in heart rate variability series in both stimulation frequencies and also in the PD spectra with significant coherences 0.5. These findings suggest that blood pressure fluctuations propagate to the pupil via carotid baroreceptors afferent pathways. However a central contribution can not he excluded. Keywoals - pupil diameter fluctuations, heart rate variability, baroreceptors, spectral analysis
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
