The relationship between behavioral awakening (button-pressing) and EEG-defined awakening (the occurrence of alpha activity) during night sleep was investigated. Polysomnograms were recorded in the laboratory from 5 adult males and 5 adult females over six successive nights. Subjects were instructed to press a button four times (behaviorally signalled awakening ; BSA) whenever they perceived their own awakenings from sleep. Results were as follows ; (1) 121 (59.8%) of all EEG-defined awakenings (206) were not signalled, (2) this dissociaton was larger on the first night than on subsequent nights and became smaller as the sleep cycle progressed, and (3) morning recall of signals was significantly correlated with the actual number of signals in a night. Results indicate that the presence of alpha activity during night does not necessarily reflect the conscious experience of awakening, and that adaptation to the laboratory and the time course of a night influence the subjective experience of awakenings in the sleeping human. The findings in our study suggest the validity of use of EEG criteria as awakening from sleep.

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The present study investigated possible changes in the skin potential levels (SPLs) before and after menstruation. Fifty two unmarried undergraduates without premenstrual tension were tested during the three periods ; 1) within 7 days before menstruation, 2) during menstruation and 3) after menstruation and within 10 days from the onset of menstrual flow. Each test consisted of a rest session (10min) and a stimulus session (20min). Auditory stimuli, 80dB tone bursts, were binaurally presented through earphones. SPLs were derived from the left palmer thenar eminence. The SPLs gradually increased in negativity from 7 to 4 days before menstruation and stayed at a negatively high level until the onset of menstruation (“Premenstrual SPLs”). The SPLs showed a decrease during the menstrual phase and maintained relatively constant during the period of 4-10 days from the onset of the menstruation (“Postmenstrual SPLs”). With respect to the order effect of the three tests, 1st “Postmenstrual SPLs” were negatively higher than 2nd and 3rd SPLs. However, “Premenstrual SPLs” showed no significant order of fect, suggesting poorer habituation in the premenstrual phase. To exclude the order effect, 2nd and 3rd SPLs were combined, and “Premenstrual SPLs” and “Postmenstrual SPLs” were compared. “Premenstrual SPLs” were significantly higher than “Postmenstrual SPLs” in the both rest and stimulus sessions, suggesting autonomic hyperarousal in the premenstrual phase.

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CNV is a complex wave that consists of early (O wave : orienting response) and late (E wave : expectancy) components. The purpose of this experiment was (1) making a mathematical model of these components, and (2) applying the model to the CNV waves obtained by time discrimination tasks. The O wave was represented by a probability density function of the Poisson process that declined slowly. Whereas the declining processes in the nature are usually represented by a sort of this function, our 'expectancy'is a kind of goal directed process (for example time discrimination by counting down). Then the model of E wave was assumed as “backward Poisson process function” which is a mirror image of the O wave model. EEG was recorded at Cz from one well trained subject. The task was to discriminate whether a test interval of two stimuli was identical with the standard interval. The standard interval (CUE) was 3200ms which was divided into each 800ms intervals by five pip tones. Three test intervals were 2400 (T-), 3200 (TZ), 4000ms (T+). Motor response was required 2000ms after each discrimination. In CUE, TZ and T + conditions, the residual wave being subtracted the model wave from the averaged CNV was a rhythmic wave with about 800ms period, which was synchronized to the stimulus pattern. This wave was assumed the'counting'component. The number of the model parameters was assumed one (form) in the O wave and two (form and amplitude) in the E wave. Possible external condition determining these parameters was discussed.

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The dual process model (Yoshida, 1990a) was applied to visual evoked potentials to double flashes (double-VEPs). A small light disk subtending 2 or 5 degrees in visual angle was presented at different contrast levels of 1.0, 2.2, and 3.4. A pulse-light with the duration of 10 ms was repeated twice as a double flash with the intervals of 50,100, and 200 ms. Typical double-VEPs from the midline occiput (Oz) were analyzed. It was hypothesized that a simplified pulse VEP model consisted of only the onset components and excluded the offset components. Parameters of the VEP models were determined by Fletcher-Powell and multiple regression methods. Synthesized model waves were found to fit well the raw double-VEPs. The second VEP models had alomost identical amplitudes all over the interval conditions. Theoretical curves of double-flash threshold showed the same effects of stimulus size and contrast as did psychophysical discrimination curves. The simplified pulse VEP model used here is assumed to be useful for the analysis of the human visual system.

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The purpose of this study was to investigate effects of widely used labolatory stressors such as mental arithmetic, a stress film, and a cold pressor test upon respiratory activities and to find parameters which show a consistent change to various steressors. Seven parameters measured in this study were : 1) breath time, 2) inspiratory time, 3) expiratory time, 4) post expiration pause time, 5) inspiratory volume, 6) expiratory volume, and 7) minute ventilatory volume. Post expiration pause time was the amount of time when expiratory flow volume dropped to 100ml/sec or less. Twenty healthy undergraduate males participated in all three sessions in the following fixed order : mental arithmetic, the stress film, and the cold pressor test. Each session consisted of one stressful task and one or two non-stressful tasks. Respiratory parameters showing a consistent change to different stressors were the minute ventilatory volume and the post expiration pause time. Minute ventilation significantly increased and pause time significantly decreased to a stressful and a non-stressful stimulus. These two respiratory parameters can be used to mark a relaxation response since they responded sensitively to mild psychological timuli.

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