International journal of psychophysiology : official journal of the International Organization of Psychophysiology
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Int J Psychophysiol · Jul 1993
Defensiveness, anxiety and the amplitude/intensity function of auditory-evoked potentials.
This study measured relationships between defensiveness, anxiety, and auditory-evoked potentials to tones of varied intensity. Subjects were designated as defensive if they scored > or = 7 on the L-scale of the Eysenck Personality Questionnaire, and high-anxious if they scored > or = 11 on the N-scale. Four groups resulted: 'high anxious', 'defensive high anxious', 'repressors' (i.e., defensive low anxious) and 'low anxious'. ⋯ High-defensive subjects showed lower P2 amplitudes to the 94 and 104 dB tones and lower amplitude/intensity slopes at FZ, CZ, C3 and C4. High-anxious subjects showed lower P2 amplitudes to all four stimulus intensities at FZ, CZ and PZ. The results are consistent with the hypothesis that defensiveness is associated with desensitization to intense or painful stimulation.
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Int J Psychophysiol · Jan 1992
Randomized Controlled Trial Clinical TrialStimulus rise time, intensity and the elicitation of unconditioned cardiac and electrodermal responses.
In recent discussions on the differentiation of orienting, startle and defense responses, the importance of stimulus rise time for the elicitation of different cardiac response patterns was re-emphasized. Especially, it has been claimed that phasic accelerative heart rate (HR) responses-interpreted as indicators of startle-might not only be evoked by auditory stimuli with instantaneous rise times and high intensities, but also by low to moderate stimulus intensities with sudden onsets. The present study examined this question by manipulating rise time (instantaneous vs. 50 ms) and intensity (60 vs. 95 dB). ⋯ As a consequence of stimulus change, larger SCRs as well as larger decelerative HR responses were observed without, however, being affected by the direction of the change in rise time. In sum, the present study suggests that the role attributed to rise time with respect to eliciting qualitatively different cardiac response patterns has been exaggerated. The consequences for the differentiation of different unconditioned responses are briefly addressed.
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Int J Psychophysiol · Aug 1991
Heartbeat perception, instructions, and biofeedback in the control of heart rate.
The present study was designed to examine the possibility that individual differences in heartbeat perception and instructions to control heart rate (HR) may influence the acquisition of voluntary control. Good (n = 20) and poor (n = 20) perceivers of cardiac activity were selected on the basis of their performance according to Whitehead et al. (1977) heartbeat discrimination procedure. Measures of state and trait anxiety (the State-Trait Anxiety Inventory Form X-1 and Form X-2) and Tellegen's Absorption Scale (TAS) were used to assess emotionality and absorptive ability. ⋯ However, more pronounced HR increases were obtained in the feedback as compared with the no-feedback condition. SC and EMG activity were in accordance with arousal levels demanded by HR decrease and increase tasks. Subjects used cognitive strategies concerning activation responses during HR-increase and relaxation responses during HR-decrease conditions.
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Int J Psychophysiol · Dec 1990
Comparative StudyEEG correlates of hypnotic susceptibility and hypnotic trance: spectral analysis and coherence.
EEG was recorded monopolarly at frontal (F3, F4), central (C3, C4) and occipital (O1, O2) derivations during A-B-A conditions of waking rest, hypnosis (rest, arm immobilization, mosquito hallucination, hypnotic dream), and waking rest. Stringently screened on several measures of hypnotic susceptibility, 12 very low hypnotizable and 12 very highly hypnotizable, right-handed undergraduate, subjects participated in one session. Evaluations were Fast-Fourier spectral analysis, EEG coherence between selected derivations and maximum spectral power within EEG bands. ⋯ Mean alpha power was never a predictor of hypnotic susceptibility. Interactions with hypnotic susceptibility showed that highly susceptible subjects had more beta activity in the left than right hemispheres, while low susceptible subjects showed only weak asymmetry. No main effects for or interactions between waking/hypnosis and hypnotic level were found for coherence between derivations or maximum spectral power within theta, alpha and beta EEG bands.
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Int J Psychophysiol · Mar 1989
40-Hz EEG asymmetry during recall of emotional events in waking and hypnosis: differences between low and high hypnotizables.
Sixteen high and thirteen low hypnotizable women, who had participated in our previous study (De Pascalis et al., 1987), were enrolled in a hypnotic session. After the hypnotic induction they were requested to recollect 2 positive and 2 negative personal life experiences. In our previous study subjects performed similar tasks in a waking-state. ⋯ The Tellegen Absorption Scale was found positively related to hypnotizability and with the level of 40-Hz density increase on the right hemisphere during emotional tasks. High hypnotizables, with respect to the lows, were able to access affects more readily. They also showed a greater hemispheric specificity in waking and hypnotic conditions.