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Biomedical subjects

J Bushman

Publications and source records attributed to J Bushman.

6 recordsLinked to original sources
PubMed1984

Changes in the pattern reversal visual evoked potential as a function of inspired nitrous oxide concentration.

The VEP to pattern displacement was measured at different levels of inspired N2O concentrations in air in 10 normal subjects. The inspired concentrations were 10, 20, 30 and 40% N2O. Expired CO2 concentrations were also measured. Ten normal controls went through the same procedure but breathed air on each trial rather than N2O. The results showed a significant decrease at 10%, almost at 20% and again significant at 30% and 40% for the amplitude of the N65-P95 wave. The P95-N125 wave was more resistant--10% was not significant, 20% was again nearly significant and 30% and 40% were significant. There were no latency changes. Because of the wider variance between group comparisons there was a significant reduction at 40% only for the N65-P95 wave and no significant difference for the P95-N125 wave. There was some evidence that the amplitude of the early components was still significantly reduced after the end of the experiment.

Adult↗
PubMed1979

Contingent negative variation and evoked potential amplitude as a function of inspired nitrous oxide concentration.

Nine subjects were given to breath 10%, 20%, 30% and 40% nitrous oxide in oxygen. The inhaled gas concentrations were monitored by a mass spectrograph. At each gas concentration the CNV was measured in a standard long S1-S2 CNV paradigm to a click and tone with a mandatory button press at S2. The results confirmed the previous observations of Lader and Morris (1974) that the cortical evoked potential decreases rapidly with increasing concentrations of nitrous oxide. The CNV, however, against prediction remains surprisingly well preserved up to the borders of unconsciousness. In this situation there is little correlation between CNV amplitude and attention, arousal or reaction time.

Adult↗
PubMed1977

Metabolic and EEG changes during transcendental meditation: an explanation.

Two experiments were conducted to measure the oxygen uptake (Experiment II) and the carbon dioxide production (Experiment I) during transcendental meditation. A control group of non-meditators and a few meditators listening to music was used for both experiments. In Experiment I, a controlled group of fasting meditators was also included. A drop in oxygen consumption and carbon dioxide production, found by previous authors during transcendental meditation, was confirmed. It was, however, possible to show that these drops were physiologically of small significance, and were of the magnitude to be expected from muscle relaxation. EEG recordings were taken during Experiment II in the meditating group. The EEG results showed transcendental meditation to be a method of holding the mediator's level of consciousness at stage 'onset' sleep. No evidence could be found to suggest that meditation produced a hypometabolic state beyond that produced by muscle relaxation and there was no evidence that the EEG changes were different from those observed in stage 'onset' sleep. No support was found for the idea that transcendental meditation is a fourth stage of consciousness.

Analysis of Variance↗