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Volume 12 (1994)
- Issue 2 Pages 51-
- Issue 1 Pages 1-
Volume 12, Issue 1
Displaying 1-5 of 5 articles from this issue
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Effects of preceding stimuliKazuya SUZUKI1994 Volume 12 Issue 1 Pages 1-9
Published: June 30, 1994
Released on J-STAGE: November 27, 2012
JOURNAL FREE ACCESSThis study examined the effects of preceding stimulus types on the attention-related negative waves (Nd waves) of event-related brain potential (ERP), especially on the amplitudinal decreases caused by dividing one's attention to multiple sound sources. Pure tones of 100ms in duration were presented repeatedly to either the right or left ear at random intervals (either 200ms or 600ms in stimulus onset asynchrony [SOA]). Twelve human subjects performed target detection tasks in a designated ear (selective attention task) and in both ears (divided attention task). The Nd wave attenuation caused by dividing one's attention was compared between differing preceding stimulus direction (same or oposite) and differing preceding SOA (either 200ms or 600ms). In this study, no noticeable differences between preceding stimulus types were observed, suggesting that neither increases in the frequency of processing nor spatial shifts in attention are significant causal factors in Nd attenuation. Therefore, the division of one's attention among spatial locations is necessary.View full abstractDownload PDF (1283K) -
Shigeru YOSHIDA1994 Volume 12 Issue 1 Pages 11-18
Published: June 30, 1994
Released on J-STAGE: November 27, 2012
JOURNAL FREE ACCESSComputer simulation was carried out for the dual process model of visual evoked potentials (VEPs) to on-off, pulse, double, and train light stimuli (e. g., Yoshida, 1990a). Simulation programs were coded as a “dynamic system” with a simulator (Extend v 1.1) working on a personal computer. A new parameter included in the model was a stimulus value derived from light adaptation, which plays an important role in a dynamic system. A reciprocal triggering mechanism in the on-off system was hypothesized to realize the after discharge of VEPs. For simplification, stimulus conditions were restricted as follows : stimulus size was five degrees in diameter and contrast was high (3.5 in ratio). Basic parameters were the same as those estimated in the former studies of VEPs. The time constant of adaptation and the amplitudes of after discharge were empirically determined. The model waves showed the fundamental features of raw VEPs in the respective conditions of stimulus modulation. The dynamic system simulation of VEP seemed to be valid to represent a structure of the visual system in the computational approach.View full abstractDownload PDF (950K) -
Naohito FUJIWARA, Hayao IMASHIOYA1994 Volume 12 Issue 1 Pages 19-28
Published: 1994
Released on J-STAGE: November 27, 2012
JOURNAL FREE ACCESSEvent-related potentials (ERPs) were studied with the oddball tone sequence paradigm in the non-task condition and the task condition for each 12 college students. N100, P200, P300 and mismatch negativity (MMN) were obtained in the non-task condition as well as in the task condition. In the non-task condition, N100 had a significantly higher amplitude following rare stimuli than that following frequent stimuli. P200 also showed a higher amplitude, although not significant, following rare stimuli. These results might reflect the detection of deviant stimuli (rare stimuli). The waveform and latency of P300 component in the non-task condition were similar to those in the task condition. No laterality effect was found in any of components. Posture change (sitting and supine) did not affect the ERP results. It was suggested that combined investigation of P300 with other components might give more precise information in the non-task condition as well as in the task condition, in terms of applied physiological psychology.View full abstractDownload PDF (1289K) -
Hiroshi NITTONO, Yasuhiro NAGEISHI, Yoshiaki NAKAJIMA1994 Volume 12 Issue 1 Pages 29-37
Published: June 30, 1994
Released on J-STAGE: November 27, 2012
JOURNAL FREE ACCESSIt has been suggested that the P300 component of the event-related brain potential is a manifestation of the brain activity which updates one's internal model of the environment. Recently, Ullsperger and his colleagues have attempted to explain the change of P300 amplitudes within the framework of Helson's “adaptation-level theory.” In the present study, we examined their hypothesis by using a symbolic stimulus discrimination task. Equiprobable and randomized sequences of five successive alphabet letters (Q-U) were presented. Subjects (n=8) were required to respond to each letter with a corresponding finger of the right hand. Although the adaptation-level model couldn't apply to this task, like Ullsperger et al.'s experiments, an “U-shaped” trend of P300 amplitude changes was found. Their model was extended in order to explain the results of this experiment. In the revised model, it was assumed that “a reference point” was used in the stimulus-evaluation process which was related to the response dimension, and that the P300 amplitude reflected the distance between this reference point and the eliciting event.View full abstractDownload PDF (1193K) -
Kazunari IKEDA, Takashi MOROTOMI1994 Volume 12 Issue 1 Pages 39-44
Published: June 30, 1994
Released on J-STAGE: November 27, 2012
JOURNAL FREE ACCESSThis study examined asymmetries of behavioral awakenings as indicated by left (L) and/or right (R) button-pressings during nocturnal sleep in humans. Subjects were instructed to press buttons with both hands simultaneously 3 times whenever they noticed their own awakening from sleep. Two adult males slept in the laboratory totalling 34 nonconsecutive occasions. The results indicated that asymmetries of behavioral awakenings (L>R or L<R) occurred more preferentially from NREM sleep than from REM sleep. The results do not support the view that each of REM and NREM sleep is associated with differential activation of the two cerebral hemispheres. Rather they suggest that REM sleep is associated with relative hemispheric symmetry whereas asymmetries are prominent in NREM sleep.View full abstractDownload PDF (680K)
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