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Biomedical subjects

R J Barry

Publications and source records attributed to R J Barry.

101 records · Page 6Linked to original sources
PubMed1966

Transfer of propionate by rat small intestine in vitro.

1. The transfer of propionate by sacs of rat everted intestine has been investigated in relation to a number of physico-chemical factors which affect movement of weak electrolytes.2. Neither the observed movement nor the distribution of propionate can be accounted for by the theory of non-ionic diffusion or by modifications of it, such as the microclimate hypothesis or partial permeability to ions.3. It is not possible to account for the observed propionate movement by the electrical potential across the gut or by solvent drag.4. The most satisfactory explanation for the observations is a transfer process in the gut for volatile fatty acids, and some features of this are discussed.

Animals↗
PubMed1966

Handling of glycerides of acetic acid by rat small intestine in vitro.

1. When mono-, di- and triacetins are incubated with sacs of rat everted intestine, they enter the epithelial cells and are hydrolysed to free glycerol and acetic acid.2. The rate-limiting step in the process is the entry of glyceride into the epithelial cell.3. The three acetins enter the epithelial cell at the same rate, and the mechanism of this remains unknown.4. The acetate released appears in higher concentrations on the serosal side, and the relation of this to the mechanism for transfer of volatile fatty acids is discussed.5. It is not necessary to postulate a special mechanism for entry of volatile fatty acids into the cell.

Acetates↗
PubMedDate not supplied

Verbal conditioning of stimulus significance in the orienting response context: an exploration demonstrating a new personality effect.

The manipulation of stimulus significance, by instructions from the experimenter, may be taken as an example of verbal conditioning. Consideration of such a mechanism suggested that personality effects previously found in conditioning studies should be apparent in instructional manipulations of significance in a study of the orienting response (OR) to words. Because of recent changes in dimensioning of the personality structure, some of the items originally used to define Eysenck's extraversion (E) dimension are now used to assess the new dimension of psychoticism (P), suggesting that at least some of the established effects of E upon conditioning may be associated now with P. Hence the P scale was focused on in this study. Words differing on the evaluative dimension of the semantic differential were presented in three blocks, the first under indifferent instructions, the second under instructions to rate the words for their affective impact, and the third under indifferent instructions again. These blocks correspond to baseline, conditioning, and extinction conditions respectively. Electrodermal activity indicated enhanced conditioning, together with greater carry-over effects in the extinction phase, for low-P compared with high-P subjects. The results indicate the importance of personality effects in studies of stimulus significance and illustrate the value of the verbal conditioning mechanism in this area of the OR field. They also suggest the need to re-examine previously obtained E-effects in conditioning studies in light of changing personality tests.

Acoustic Stimulation↗
PubMedDate not supplied

The orienting response: stimulus factors and response measures.

This paper outlines some of the basic ideas of the orienting response (OR) that have developed from the classical writings of E.N. Sokolov, in particular the effects of stimulus novelty, intensity, and significance upon the OR, and predictions about these effects on a range of physiological measures traditionally associated with the OR. Such measures include the GSR, respiration, heart rate, vascular responses, EEG, and pupil diameter. Unfortunately, many of the predictions of classical OR theory do not hold up when such a fine-grain analysis is undertaken. Possible conceptualizations of the discrepancies between Sokolovian predictions and empirical data are considered--should we accept such discrepancies as merely reflecting the imperfect nature of many OR indices, or seek other regularizing principles? Preliminary Process Theory has been proposed as one alternative account of the existing data base, and similarities and differences between it and Sokolovian theory are explored. The need for further investigation of such problems, in the very foundations of OR theory, appears to be of fundamental importance to the future status of the OR. An appendix provides a discussion between Barry and Sokolov on some of these issues.

Animals↗
PubMedDate not supplied

Applied orienting response research: some examples.

The development of orienting response (OR) theory has not been accompanied by many applications of the concept--most research still appears to be lab-based and "pure," rather than "applied." We present some examples from our own work in which the OR perspective has been applied in a wider context. These cover the exploration of processing deficits in autistic children, aspects of the "repression" of anxiety in elite athletes, and the locus of alcohol effects. Such applications of the OR concept in real-life situations seem a logical and, indeed, necessary step in the evolution of this area of psychophysiology.

Alcohol Drinking↗
PubMedDate not supplied

Signal value and preliminary processes in OR elicitation.

The evoked cardiac response (ECR) of heart rate deceleration, respiratory pause, the peripheral pulse amplitude response (PPAR) of vascular constriction, and the galvanic skin response (GSR) were recorded from 20 subjects presented with a series of brief target and nontarget stimuli in a random order. Prestimulus vigilance was equivalent for the two types of stimuli since each had to be identified as target or nontarget before being processed, or ignored, respectively. This difference in signal value following identification affected only by the GSR, supporting a conceptualization of preliminary processes in orienting response (OR) elicitation rather than Sokolov's unitary OR concept.

Adult↗
PubMedDate not supplied

Heart rate deceleration is not an orienting reflex; heart rate acceleration is not a defensive reflex.

Graham and Clifton (1966) proposed an integration of Sokolov's theory of orienting and defensive reflexes with the stimulus intake/rejection dichotomy of the Laceys. This integration consisted of hypothesizing that heart rate deceleration is a measure of the orienting reflex, and that cardiac acceleration is a measure of the defensive reflex. This article demonstrates that Graham and Clifton failed to establish a valid integration of these two theories. This failure is a consequence of 1) their misconstruing Sokolov's theory, and 2) an inaccurate and selective review of the research literature then available. Consideration of more recent research would seem to rule out the possibility that their thesis was correct in spite of these flaws in its derivation. Cardiac responding in the OR context thus remains open to further investigation and interpretation.

Acoustic Stimulation↗
PubMedDate not supplied

The relationship between quantified EEG and skin conductance level.

Electroencephalographic measures (EEG) and skin conductance level (SCL) respectively reflect cerebral cortical activity and sympathetic autonomic activity. Such central and autonomic activities associated with arousal generally have been studied separately, despite their potential to reflect complementary dimensions of reticular-thalamo-hypothalamo-cortical activating networks. In this study, we examined the relationship between cortical (19 EEG sites) and autonomic (SCL) activities recorded simultaneously in 10 normal adults. Two second pre-stimulus EEGs and SCLs were assessed from an habituation paradigm which presented 22 trains of 7 tones in an 'ignore' condition. The mean SCLs of the epochs across subjects showed an initial rise (sensitization) followed by an exponential decline (habituation). Although EEG associated with the tones did not demonstrate such a distinct profile, EEG total power and band powers (beta, alpha and theta) associated with the trains showed a systematic increasing response profile. In the group data the mean SCLs within trains showed a significant correlation with alpha and beta band powers. Finer EEG band analyses indicated that beta 3 at Fz and alpha 2 at Cz showed the strongest separate linear correlations with SCL. beta 3 and alpha 1 at Fz were found to jointly covary with SCL. The findings indicate a substantive relationship between measures of cerebral function and autonomic arousal.

Acoustic Stimulation↗
PubMedDate not supplied

Electrodermal responses to emotive and non-emotive words as a function of personality differences in affect level.

This study examined the use of the P scale of the Eysenck Personality Questionnaire as a pencil and paper estimate of level of affect lability. Groups of subjects differing on the P scale were presented with emotive and non-emotive words. High P (low affect) subjects appeared inhibited in their emotional rating of all words, and displayed a restricted range in their reporting of this rating. Further, the electrodermal activity elicited by these words differed between the groups, with high P subjects again appearing relatively inhibited. These results support the validity of the P scale as a measure of affect lability and have implications for a recent hypothesis of impaired functioning of the reticular activating system in early-onset psychosis. The results may also be interpreted to support the role of significance in elicitation of the orienting response.

Adult↗