399 tape recorder. Later on in the experiment the subjects reproduced the stored respiratory signals which were presented in form of moving horizontal bar on the oscilloscope screen. In EOG the spontaneous eyeblinks were detected and classified into three groups according to their relation to three phases of respiration - inspiration, expiration and post-expiratory pause. The lengths of these three phases were measured in every respiratory cycle. The mean eyeblink-rates and the mean durations were calculated for every respiratory phase in all conditions and subjects. Three-way ANOVA’s (3 PHASES, 2 STATES - Rest vs. MA, 2 MODES of breathing - spontaneous vs. voluntary) were performed for eyeblink-rates and lengths of respiratory phases. The ratios of inspiratory/expiratory eyeblinkrates as well as ratios of inspiratory-expiratory lengths were also calculated. These values entered another three-way ANOVA (2 RATIOS - lengths vs. eyeblinkrates, 2 STATES, 2 MODES). The effect of PHASES was significant by eyeblinkrates (F/2, 144/=14.3, p
breathing which cannot be explained by temporal characteristics of the respiratory phases. Finally, the correlation coefficients between eyeblink-rate ratio and length ratio were computed for spontaneous and voluntary breathing. There was positive correlation 0.51, pcO.01 in spontaneous breathing and negative correlation 4.59, ~~0.01 in voluntary breathing. Summary: We found higher eyeblink-rate in expiratory phase relative to the inspiratory one in resting condition, mental arithmetic and during voluntary breathing. In spontaneously breathing man this phenomenon was associated with temporal characteristics of the respiratory curve. On the other hand, quite different respiratory-eyeblink coupling was found in voluntary breathing. In the latter condition the increased frequency of eyeblinks in expiration was negatively correlated with relative prolongations of the expiratory phase of the respiratory cycle. References
Dosdlek, C. and K&a, H. (1976) Vliv dechove faze na tvorbu podmineneho reflexu u Cloveka. CeskoslovensM Fyziologie, 20: 225-226. SK&&, A., Fabian, Z., Dosdlek, C. (1987) Spectral analysis of inter-eyeblink interval sequence in man. Interdisciplin. study of higher nervous functions - 2nd European CIANS Conference, Magdeburg: Abstr. p. 92.
NOCTURNAL SLEEP - SUBJECTIVE AND OBJECTIVE EVALUATION I. Stoilova Brain Research Institute, Bulgarian Academy of Science, Sofia, Bulgaria The precise evaluation of the quality of nocturnal sleep acquires the character of a scientific task of great importance for practice, especially with respect to people performing complex professional activities under extreme conditions. The study of the structure and qualities of nocturnal sleep is a principal method in determining man’s general functional state and his adapting to different extreme impacts. The precise evaluation of nocturnal sleep makes it possible to predict possible changes in man’s working ability and to undertake steps for its optimization.
400 The polyphysiographic registration of nocturnal sleep permits its objective evaluation after the necessary processing and analysis of the data. Very often the subjective evaluation given by the person whose nocturnal sleep is being registered differs essentially compared with the objective evaluation performed, whereby the differences most often concern the duration, depth, interruptions of the sleep, etc. Such data are usually obtained in experiments studying individuals with high motivation in which the result of the investigation may influence the decision of a commission of experts (e.g. in tests for selecting candidates for different professions - aquanauts, pilots, astronauts, etc.). A series of experiments were carried out, whereby sleep of aquanauts was traced systematically under hyperbaric conditions in a pressure chamber. The registrations of nocturnal sleep covered a prolonged period (20 to 30 days), comprising all stages of the hyperbaric experiment (compression, decompression, stay at ground level, prior to and after the hyperbaric impact). An interesting dynamics is observed in the structure and organization of nocturnal sleep, but parallel with this very often there were essential differences between the objective evaluation and the subjective evaluation of the subjects investigated. However, most frequently the objective analysis demonstrated better results: the percentage content of the different sleep phases was within normal limits, whereas the subjects reported a feeling that their sleep had not been sufficient or that it had been predominantly superficial. The analysis of the organization of sleep has shown, however, that these were cases not of insufficient sleep, but most frequently of a more peculiar redistribution of these sleep phases (deep sleep stages III + IV). The deep phases of sleep were, “accumulated” predominantly in the first hours of the night, being sufficient in quantity, but incorrectly distributed. The organism needed these stages, because it is precisely they that are related to the energy restoring processes, and it has produced them, but this had happened much faster under extreme than under normal conditions. The superficial sleep recorded afterwards during the rest of the night until the subject awoke had left the impression of a predominantly superficial sleep and an insufficient quantity of deep sleep. This essential difference in the objective and subjective evaluations of sleep should always be borne in
mind when the evaluation of sleep to he used as an indicator of the general functional state, for evaluating man’s working ability, etc.
DURATION ESTIMATION OF UPRIGHT AND INVERTED FACES PRESENTATION Y. Stoyanova, Z. Bohdanecky* Institute of Physiology, Bulgarian Academy of Sciences, Sofia, Bulgaria, *Institute of Physiology, Czechoslovak Academy of Sciences, Prague, Czechoslovakia Many non-temporal variables, such as intensity, contrast, complexity, meaningfulness, familiarity, form, area etc. have been shown to influence perception of both long and short time instants estimation. Some of these factors (intensity, contrast etc.) affect recognition performance. We suggest that the ease of recognition performance underlies the effect of some non-temporal variables of brief duration perception. This assumption testing was done by recognition manipulating, keeping all physical characteristics of the stimuli unchanged. This was achieved using upright and inverted faces as stimuli recognition of them is particularly prone to disruption when faces are inverted. High intensity, high contrast or greater familiarity enhance recognition on one hand and lead to longer subjective duration on the other hand. We can thus predict a positive correlation between duration estimates and recognition accuracy: duration estimates were expected to be greater in the case of easier recognition, i.e. for facial stimuli in upright position. Ten black-and-white photographs of pleasant and unpleasant faces represented the stimulus set. Both types of faces were presented in upright and inverted position. The slides were rear-projected on a white translucent screen in the form of two-channel projection tachistoscope. A brief appearance of the facial stimuli interrupted the constant presentation of a visual noise masking pattern. Neutral density filters equalized the mean luminance of the stimuli and the maks, producing thus an illumination of 40 lx at the subject’s eyes level. The visual angle subtended by the image was approximately 10 x 10 degrees of visual angle, depending on the sitting position of the subject, who sat