Biomedical subjects

J S Antrobus

Publications and source records attributed to J S Antrobus.

12 recordsLinked to original sources

PubMed1997

REM sleep eye movement counts correlate with visual imagery in dreaming: a pilot study.

Based on the findings of our previously published positron emission tomography study, we proposed that recorded eye movements during REM sleep are visually targeted saccades. In the present study, we examined the correlation between the number of eye movements in REM sleep (EM) and visual imagery in dreaming (V) and provided further support for our proposal. All the observations (N = 11) were made with one individual to eliminate interindividual variation and were made during the second REM sleep period to control for a time-of-night effect. V, with or without dream report length partialled out, was strongly associated with EM only in the 1-min interval immediately preceding awakening. The time course of the association suggests that the strong EM-V association reflects a phasic, localized activation of the eye-movement-control system in association with REM sleep eye movements.

Adult↗

PubMed1997

The effect of presemantic acoustic adaptation on semantic "satiation".

A decrement in the strength of the meaning of a word after rapid repetition of that word has been called "semantic satiation." This study asked whether this "satiation" might be produced by presemantic acoustic adaptation. Category words were utilized to prime the meaning of target words. The adaptation or "satiation" procedure, 30 rapid repetitions of the primes, was compared with a control condition of 3 repetitions. Participants listened to a series of prime words, each repeated by either the same speaker or many speakers, and then made semantic decisions on target words. When all the repetitions of a prime word are produced by the same speaker, presemantic and semantic repetitions are confounded. When the repetitions are produced by different speakers, presemantic acoustic repetition is abolished. A semantic decrement was detected with single-speaker, but not with multiple-speaker, repetitions of prime words. This study concluded that the semantic "satiation" observed here was a decrement in the activation level of semantic representations induced by presemantic acoustic adaptation.

Analysis of Variance↗

PubMed1987

Cortical arousal and mentation in sleeping and waking subjects.

Cognitive variables and cortical arousal levels were examined in order to determine whether differences in cortical arousal levels within REM and waking could account for different aspects of mentation derived from the two states. Cognitive variables were derived from mentation reports collected from 30 subjects in both the waking state and after being awakened from REM sleep. Mentation reports were independently scored on seven content rating scales, by two judges blind to the conditions. These scales include among others, Total Recall Count (TRC), a count of all words in which the subject described his/her experience during the previous interval. The EEG activity, obtained from left and right midtemporoparietal and central sites, was recorded for 5-min periods before obtaining mentation reports. The absolute power of the EEG activity was calculated for each of six bandwidths. EEG power data from both waking and REM were entered into multiple linear regression equations to predict TRC. No relationships were found between TRC and general cortical activation, as measured by the EEG. Other statistical analyses, including relationships between EEG and scales of visual imagery, are discussed.

Adolescent↗

PubMed1986

Sleeping and waking thought: effects of external stimulation.

This article describes some of the variables that distinguish waking and sleeping (REM) thought. Mentation reports from the waking state, as described here, tend to have more topic shifts than those from the REM state, which often have a single-theme storylike quality. It is assumed that heightened response thresholds to sensory stimuli, in conjunction with the state of high cortical activation typical of REM sleep, account for the storylike quality of REM imagery. In this experiment, an intermittent auditory stimulus was the model for environmental influences on waking mentation. It was hypothesized that the removal of this intermittent auditory stimulation, simulating in waking subjects the increased sensory thresholds of REM sleep, would decrease the number of topic shifts in spontaneous thought. It was expected that this reduction in number of topics would approach levels achieved in REM sleep. Thirty subjects participated in individual sessions in which they lay in a sound-attenuated, lightproof room with eyes closed. They were asked for mentation reports as follows: after lying awake with external stimulation (W), after lying awake without external stimulation (WO), and after being wakened from REM sleep. Transcribed mentation reports were scored on seven content rating scales, including total recall count, a count of all words in which the subject was describing his/her experience during the previous interval, and number of thought units (TU) per report, a count of the distinct, thematically homogeneous thought sequences. Hotelling t-squared tests were performed with the different states as the independent variables and the scores on the cognitive scales as the dependent variables. The major factor distinguishing mentation reports of waking subjects and subjects wakened from REM sleep was the TU count, with waking subjects changing topics more frequently. Removal of the intermittent auditory stimulus reduced the number of topic shifts in waking subjects, with a significance approaching the 95% confidence limit.

Acoustic Stimulation↗

PubMed1985

EEG asymmetry and sleep mentation during REM and NREM.

The hypothesis that dreaming is mediated by the right hemisphere was evaluated by monitoring EEG power asymmetry during REM and NREM sleep, and obtaining mentation reports when short-term temporal shifts in the EEG indicated relative left- or right-hemispheric dominance. Content analyses provided no support for the right-hemisphere hypothesis; indeed, some scales showed higher content during relative left-hemispheric dominance. In contrast to earlier reports, no difference between REM and NREM in EEG asymmetry was observed.

Dominance, Cerebral↗

PubMed1985