ヒトの驚愕性瞬目反射におよぼす先行刺激効果

山田 冨美雄; 宮田 洋

doi:10.4992/jjpsy.49.349

LEAD-STIMULATION EFFECT UPON HUMAN STARTLE EYEBLINK REFLEX

FUMIO YAMADA, YO MIYATA

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JOURNAL FREE ACCESS

1979 Volume 49 Issue 6 Pages 349-356

DOI https://doi.org/10.4992/jjpsy.49.349

[Correction] The Japanese Journal of Psychology Vol.50 No.1 (1979) pp.58-58

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Published: March 20, 1979 Received: October 30, 1978 Available on J-STAGE: July 16, 2010 Accepted: - Advance online publication: - Revised: -
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Date of correction: July 16, 2010 Reason for correction: - Correction: ABSTRACT Details: Wrong : When a relatively weak stimulus (S₁) which does not itself evoke an overt response precedes a more intense reflex-eliciting stimulus (S₂), the reflex to the latter stimulus is modified, depending upon temporal parameters such as interstimulus interval (ISI). This phenomenon is known as ‘lead-stimulation effect’.
The lead-stimulus was a 1000Hz pure tone of 67dB (in Exp. I) or 65dB (in Exp. II). The reflex-eliciting stimulus was a 110dB white noise of 50msec duration. Eyeblink reflexes were measured by photo-sensor apparatus. There were two types of S₁ presentation, i.e., continuous S₁ (c-S₁) and discrete S₁ (d-S₁). The former continued until S₂ was turned off, and the latter continued for only 50msec.
In Exp. I the main purpose was to investigate the turning point where the lead-stimulation effect changes from inhibitory to facilitatory. Nine undergraduates (two males and seven females) received 81 trials arranged in a 9 by 9 Latin square with nine types of trials ordered in nine blocks of trials, so that each type occurred once in the block and at a different place within each block. Each subject had a different square. In each block there was one control trial in which S₂ was presented alone and eight S₁-S₂ trials in which S₁ and S₂ were both given. These S₁-S₂ trials were taken from a 2 by 4 factorial design with two types of S₁ (c-S₁ and d-S₁) and four levels of ISI (100, 200, 400 and 800msec). The mean inter-trial interval (ITI) was 35sec.
In Fig. 1 both the mean reflex amplitude and the modification ratio (MR) were plotted to show lead-stimulation effect. The reflexes were inhibited in short ISIs and facilitated in long ISIs. Statistical analyses showed that only the ISI main effect was significant. The turning point of the effects was about 400msec or less in ISIs.
In Exp. II we attempted to verify the hypotheses of facilitation effect proposed by Graham (1975). According to her hypotheses, the lead-stimulus facilitation is caused by two different processes, i.e., the “classical-activation process” and the “orienting-attentional process”. The former plays a role when the S₁ is a continuous type and the latter when the temporal uncertainty of the impact of the S₂ is high, e.g., in the variable ISI condition. Since ISIs are fixed in Exp. II, the orienting-attentional process does not come into play. It is thus expected that facilitation must occur only in the continuous S₁ condition.
Thirty six undergraduates (18 males and 18 females) received 18 S₁-S₂ trials and 18 S₂ alone-control trials. Nine subjects were randomly assigned to each of the four groups, each of which was arranged with a 2 by 2 factorial design with two types of S₁ presentation (c-S₁ and d-S₁) and two levels of ISI (100 and 2000msec). The groups were named Group c-100, d-100, c-2000 and d-2000 respectively. The mean ITI was 35sec.
The results of Exp. II are shown in Fig. 2 to 4. As shown in Fig. 2 the mean reflex amplitudes were in general habituated in both S₂ alone-control and S₁-S₂ conditions. But Group c-2000 didn't habituate in either condition. The measure of both amplitude and latency showed, as expected, that the facilitation effect was significant only in Group c-2000 and not in Group d-2000, as shown in Figs. 2 and 4. Although Group d-100 unexpectedly showed a lower reflex amplitude than Group c-100, the inhibitory effect was significant in both short ISI groups. Since the trial effect was not significant in MR, it is clear that the lead-stimulation effect is neither acquired nor of conditioning effect (Fig. 3).
It seems correct to interprete these two experiments in
Right : When a weak tone precedes a 110dB white noise, the acoustic eyeblink reflex to the latter stimulus is modified, depending upon the temporal parameters of the stimulus configuration. This phenomenon is called “lead-stimulation effect”. The purpose of this study was to clarify the turning point where the effect of the lead-stimulus upon the reflex changes from inhibitory to facilitatory, and to verify the hypotheses of facilitation effect proposed by Graham (1975). In Exp. I, nine undergraduates were tested with a variable ISI design. The results showed that the turning point was around 400msec or less in ISI. In Exp. II, 36 undergraduates were tested with a fixed ISI design. The results indicated that Graham's hypotheses were valid.

Abstract

When a weak tone precedes a 110dB white noise, the acoustic eyeblink reflex to the latter stimulus is modified, depending upon the temporal parameters of the stimulus configuration. This phenomenon is called “lead-stimulation effect”. The purpose of this study was to clarify the turning point where the effect of the lead-stimulus upon the reflex changes from inhibitory to facilitatory, and to verify the hypotheses of facilitation effect proposed by Graham (1975). In Exp. I, nine undergraduates were tested with a variable ISI design. The results showed that the turning point was around 400msec or less in ISI. In Exp. II, 36 undergraduates were tested with a fixed ISI design. The results indicated that Graham's hypotheses were valid.

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