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The effects of different environmental demands on breathing patterns and the rate of oxygen consumption
Three groups (N = 16) of student subjects were used and each group was further divided into two sub-groups presented with either slides of potentially agoraphobic or neutral material. During the first part of the experiment, subjects were exposed to 10 presentations of the slides whilst their breathing was manipulated via tape-recorded instructions. Group I was instructed to hyperventilate deeply (30 cpm), Group II was instructed to breathe at a slow rate (6 cpm) and Group III was uninstructed. After a recovery phase of about 10 min, each group was re-exposed to the slide stimuli in the form of a standard habituation paradigm. Skin conductance, respiration and heart-rate were monitored, and subjective measures of somatic and affective states were obtained throughout the experiment. The effects of breathing instructions and slide content on both physiological and subjective responses were compared across groups. The hyperventilation instructions resulted in delayed skin conductance response habituation. This difference could not be accounted for in terms of group differences in either physiological or subjective ‘arousal’. The results are discussed in relation to current theories relating hyperventilation to anxiety disorders.
MEASURES Carole
OF AIRWAYS RESISTANCE
IN PSYCHOPHYSIOLOGY
BUTLER
Deportment
of Psycholo~,
St George? Hosprtul Me&al
School, Unirwxiy
of London, London, ti. K.
Measurement of pulmonary function fall into two main categories; those which measure functional capabilities, and those which measure the resistance of the lungs to air flow. The first group of measures include peak expiratory flow rate (PEFR), forced expiratory volumes (such as FEV,) and forced vital capacity (FVC). They required the patient to perform pulmonary manoeuvres (maximal expirations) and have two disadvantages. Firstly, the measurements are effort-dependent; secondly the manoeuvres themselves may cause some change in pulmonary function. Nevertheless, the equipment required for these measures is relatively inexpensive and portable. Techniques for measuring airways resistance are highly sensitive to changes in bronchial constriction, as resistance is proportional to radius. Small changes occurring over a short period can also be assessed. These methods require the use of a mouthpiece which can cause some change in breathing pattern, but produces little alteration in pulmonary function. The whole body plelthysmograph is the method of choice as far as pulmonary measurements are concerned, but is less suitable for psychophysiological research. The forced oscilla-
J. Gruzelier, ed. / Pvychophysrolo~
Smety
abstracts, 1984
281
tion technique is a reasonable compromise and provides an index of total respiratory resistance, al though all the factors influencing the measure are not well understood. These instruments are rather more expensive than thes pirometers or peak flow meters required for the measurement of functional capability.
THE EFFECTS OF DIFFERENT ENVIRONMENTAL DEMANDS BREATHING PATTERNS AND THE RATE OF OXYGEN CONSUMPTION Jasper
ON
BRENER
Unioerslty of Hull, Hull, U. K
Experiments were conducted in which oxygen consumption (VO,) was recorded under a variety of environmental conditions in rats and humans. Variations in the rate (R,) and volume (VE) of breathing have also been recorded from human subjects. The data indicate that individuals consistently exhibit an increase in VO, on initial exposure to a novel environmental demand. This initial increase in metabolic rate is usually of a large magnitude and gradually reduces as the individual adapts to the demand. If the situation engenders a behavioral adaptation, elevated VO, levels are maintained albeit, at levels below that of the initial response. Sustained elevations in VO, are produced even by information-processing tasks that do not lead to variations in overt movement (e.g. solving anagrams). Presumably, in such cases the increased respiratory activity is produced by the metabolic demands associated with isometric muscular contractions. However, if individuals fail to adapt behaviourally to a task demand, they habituate to the environmental conditions and their VO,s drop to pre-task levels. Variations in VO, are highly correlated with variations in VE and the latter variable may be employed to index variations in metabolic rate. Furthermore, alterations in VO, are strongly associated with alterations in EMG activity and heart rate (HR) and may provide an adequate basis for explaining HR variations of the sort typically observed in psychophysiological experiments.
EEG AND EVOKED POTENTIAL THEIR INTER-RELATIONSHIPS Chairmen: Jeff JUTAI Dietrich LEHMANN
MEASURES:
MEASURES Carole
OF AIRWAYS RESISTANCE
IN PSYCHOPHYSIOLOGY
BUTLER
Deportment
of Psycholo~,
St George? Hosprtul Me&al
School, Unirwxiy
of London, London, ti. K.
Measurement of pulmonary function fall into two main categories; those which measure functional capabilities, and those which measure the resistance of the lungs to air flow. The first group of measures include peak expiratory flow rate (PEFR), forced expiratory volumes (such as FEV,) and forced vital capacity (FVC). They required the patient to perform pulmonary manoeuvres (maximal expirations) and have two disadvantages. Firstly, the measurements are effort-dependent; secondly the manoeuvres themselves may cause some change in pulmonary function. Nevertheless, the equipment required for these measures is relatively inexpensive and portable. Techniques for measuring airways resistance are highly sensitive to changes in bronchial constriction, as resistance is proportional to radius. Small changes occurring over a short period can also be assessed. These methods require the use of a mouthpiece which can cause some change in breathing pattern, but produces little alteration in pulmonary function. The whole body plelthysmograph is the method of choice as far as pulmonary measurements are concerned, but is less suitable for psychophysiological research. The forced oscilla-
J. Gruzelier, ed. / Pvychophysrolo~
Smety
abstracts, 1984
281
tion technique is a reasonable compromise and provides an index of total respiratory resistance, al though all the factors influencing the measure are not well understood. These instruments are rather more expensive than thes pirometers or peak flow meters required for the measurement of functional capability.
THE EFFECTS OF DIFFERENT ENVIRONMENTAL DEMANDS BREATHING PATTERNS AND THE RATE OF OXYGEN CONSUMPTION Jasper
ON
BRENER
Unioerslty of Hull, Hull, U. K
Experiments were conducted in which oxygen consumption (VO,) was recorded under a variety of environmental conditions in rats and humans. Variations in the rate (R,) and volume (VE) of breathing have also been recorded from human subjects. The data indicate that individuals consistently exhibit an increase in VO, on initial exposure to a novel environmental demand. This initial increase in metabolic rate is usually of a large magnitude and gradually reduces as the individual adapts to the demand. If the situation engenders a behavioral adaptation, elevated VO, levels are maintained albeit, at levels below that of the initial response. Sustained elevations in VO, are produced even by information-processing tasks that do not lead to variations in overt movement (e.g. solving anagrams). Presumably, in such cases the increased respiratory activity is produced by the metabolic demands associated with isometric muscular contractions. However, if individuals fail to adapt behaviourally to a task demand, they habituate to the environmental conditions and their VO,s drop to pre-task levels. Variations in VO, are highly correlated with variations in VE and the latter variable may be employed to index variations in metabolic rate. Furthermore, alterations in VO, are strongly associated with alterations in EMG activity and heart rate (HR) and may provide an adequate basis for explaining HR variations of the sort typically observed in psychophysiological experiments.
EEG AND EVOKED POTENTIAL THEIR INTER-RELATIONSHIPS Chairmen: Jeff JUTAI Dietrich LEHMANN
MEASURES: