SPECTRAL-ANALYSIS OF INTER-EYEBLINK INTERVAL VARIABILITY AT REST AND DURING MENTAL ARITHMETIC

Robust spectral analysis was used for description of variability of intervals between successive eyeblinks at rest and during mental arithmetic. The experiments were performed in thirteen subjects (Ss) in three identical sessions. In addition to spectral analysis of inter-eyeblink interval (IEI) variability, spectral densities of R-R intervals and respiration were also computed in one session . Three frequency bands were found in IEI spectra both at rest and during mental arithmetic - 0.11-0. 3 Hz, 0.08-0.10 Hz and 0.05-0.07 Hz. The frequency histograms of spectral peaks from IEI variability, R-R intervals and respiratory spectra revealed similarity between respiration and IEI variability in the frequency region 0.13-0.3 Hz, and between R-R interval and IEI spectra in the range of 0.1 Hz rhythm. The mean IEI was shorter, the total IEI variability was lower, and the occurrence of spectral peaks at the frequency 0.15 Hz was higher during mental arithmetic compared to rest.