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Biomedical subjects

P H Venables

Publications and source records attributed to P H Venables.

At least 19 recordsLinked to original sources
PubMed1997

Heart rate and skin conductance in behaviorally inhibited Mauritian children.

This study tested predictions that inhibited versus uninhibited children exhibit higher heart rate (HR) and skin conductance (SC) arousal. Mauritian children (N = 1,795) were tested at age 3 and classified as inhibited, middle, or uninhibited on the basis of social behavior. HR level and several SC measures were obtained immediately before or during a tone task. Inhibited children displayed significantly higher HR and SC levels and longer SC latency relative to uninhibited children. Results remained regardless of ethnicity, gender, height, weight, respiratory complaints, or crying behavior. Findings suggest that HR and SC levels may be early indicators of inhibited or uninhibited behavior at age 3 and support the notion of heightened sympathetic reactivity due to limbic arousal in inhibited children.

Arousal↗
PubMed1996

The effects of age, sex and time of testing on skin conductance activity.

An investigation of the electrodermal activity of 640 subjects was carried out in Mauritius. Results of a balanced factorial design with 5 age groups, sex, season (hot versus cold), time of day of testing (a.m./p.m.), as factors, suggested the need to take account of age and sex in studies using measures of electrodermal activity. However, season and time of day of testing are seen as important mainly in interaction with sex and give rise to the suggestion that females may be more responsive to environmental conditions than men. The results also provide data which show that a rate of electrodermal non-responsivity of about 25% appears to be constant over the age groups of 5-25 years used in the study.

Adolescent↗
PubMed1996

Schizotypy and maternal exposure to influenza and to cold temperature: the Mauritius study.

A topic of current controversy is that maternal exposure to influenza in the 2nd trimester of pregnancy may place the offspring at increased risk for schizophrenia. However, exposure to cold and to influenza may be confounded in existing studies, and case finding and identification may introduce error. Use of measures of schizotypy that are dimensional may be used to overcome some of the difficulties of case identification. Data are derived from the longitudinal study in Mauritius, an island in the southern hemisphere, where, in the case of the 1968-1972 Hong Kong/A2 influenza virus epidemic, influenza and low temperature were not confounded. The results suggest that women's exposure to influenza in pregnancy is associated with an elevation of positive schizotypy scores, whereas exposure to low environmental temperatures is associated with an elevation of anhedonia scores in their offspring.

Adolescent↗
PubMed1995

The stability of inhibited/uninhibited temperament from ages 3 to 11 years in Mauritian children.

Stability of inhibited/uninhibited temperament was assessed using 1,795 Mauritian children tested at ages 3, 8, and 11 years. Children were divided into uninhibited, middle, and inhibited groups at each age based on social behavior. Results indicated that, relative to uninhibited children (1) those inhibited at age 3 obtained larger inhibition scores at age 8 (p < .0001), (2) those inhibited at age 8 obtained larger inhibition scores at age 11 (p < .002), and (3) those remaining inhibited from ages 3 to 8 obtained larger inhibition scores at age 11 (p < .002). Relative to children who changed classification from ages 3 to 8, those remaining inhibited obtained larger inhibition scores (p < .05) and those remaining uninhibited obtained smaller inhibition scores (p < .015) at age 11. Inhibition scores tended to be higher in females by age 11. Results remained regardless of ethnicity. The results provide some support that inhibited/uninhibited temperament remains stable from ages 3 to 8 and may continue to age 11. The results suggest cross-cultural generalizability of these findings with implications regarding the development of anxiety disorders in the Mauritian population.

Anxiety Disorders↗
PubMed1995

High autonomic arousal and electrodermal orienting at age 15 years as protective factors against criminal behavior at age 29 years.

OBJECTIVE: Nothing is known about biological factors that protect a predisposed individual from becoming criminal. This 14-year prospective study tested the hypothesis that antisocial adolescents who desist from crime by age 29 have greater physiological arousal and orienting than antisocial adolescents who become adult criminals. METHOD: Physiological arousal and orienting were measured in 101 unselected 15-year-old male schoolchildren. Of these, 17 antisocial adolescents who desisted from adult crime (desistors) were matched on adolescent antisocial behavior and demographic variables with 17 antisocial adolescents who became criminal by age 29 (criminals), and 17 nonantisocial, noncriminal normal subjects. RESULTS: Desistors had significantly higher electrodermal and cardiovascular arousal and higher electrodermal orienting than the criminal group. CONCLUSIONS: This is the first study to report biological factors that protect against the development of criminal behavior. The findings suggest that individuals predisposed to adult crime by virtue of showing antisocial behavior in adolescence may be protected from committing crime by high levels of autonomic arousal and orienting.

Adolescent↗
PubMed1994

The relationship of sweat gland count to electrodermal activity.

This study assessed whether greater skin conductance activity at the distal versus medial site (Scerbo, Freedman, Raine, Dawson, & Venables, 1992) is attributable to a greater number of active (open) sweat glands at the distal site. The number of sweat glands was measured using the Palmar Sweat Index (PSI). Twenty-four subjects were exposed to 10 auditory stimuli. Electrodes were placed on the fore and middle fingers of each hand, using distal sites on one hand and medial sites on the other. The PSI was measured at the medial and distal phalanges adjacent to the electrode placement sites. The distal site contained more open and total sweat glands. Open gland count had the strongest correlations with skin conductance. Multivariate analyses of covariance revealed that site effects for nonspecific and orienting response frequency and trials to habituation were associated with site differences in open glands. Skin conductance measures and the PSI reveal greater electrodermal activity at the distal site. In addition, the number of open glands may be a useful measure related to electrodermal response frequency when polygraph measurement is unavailable.

Acoustic Stimulation↗
PubMed1994

The structure of schizotypy, its relation to subdiagnoses of schizophrenia and to sex and age.

A growing amount of evidence suggests that the generally accepted division of schizophrenic symptomatology into positive and negative aspects should be extended to include a third major aspect, namely 'disorganization/social impairment'. As schizotypy can be seen as the non-pathological counterpart of schizophrenia, possibly brought about by the same 'schizotaxic' predisposition(s), it might be expected that the multidimensionality of schizotypy would reflect the tripartite structure seen in schizophrenia. Although the data from studies using scales to measure schizotypy do not clearly support this view, this is mainly because of the relative lack of comparability among the scales used in different studies. Results from the present study, which involve the factor analysis of items rather than scales derived from the testing of a large and diverse population of normal subjects, does, however, support the view that measures of schizotypy may be grouped in a parallel way to symptoms shown by populations of schizophrenic subjects. The suggestion may thus be made that the symptom groupings shown by schizophrenics may be seen as primary and not the secondary result of reactions to earlier phases of the illness. The role of sex and age in the determination of scores on schizotypic dimensions is also examined and show that the sex and age differences found in subdiagnostic categories in schizophrenia are reflected in dimensions of schizotypy.

Adolescent↗
PubMed1992

Disorder of attention in individuals with schizotypal personality.

This study was designed to examine disorder of switching attention in normal individuals with schizotypal personality. High scorers on the physical anhedonia (PA) and schizophrenism (SZ) scales of a questionnaire constructed to measure schizotypy were compared with a group of control subjects. A reaction time test was used that required switching attention across or between auditory and visual modalities. It was found that the high PA scores and the high SZ scorers showed a deficit of shifting attention across modalities compared with the control subjects.

Adult↗
PubMed1992

A major effect of recording site on measurement of electrodermal activity.

Although the medial phalanx has been recommended as the preferred site for recording skin conductance activity, a review of articles published in Psychophysiology indicates that a large minority (34%) of studies employ the distal phalanx. Informal observations also suggest that the distal site may be more reactive than the medial site. This study formally tests this observation by recording skin conductance from both medial and distal phalanges. Twenty-four right-handed subjects (12 male, 12 female) were exposed to a series of 10 orienting and defensive stimuli. Electrodes were placed on the fore and middle fingers of each hand, with distal sites used on one hand and medial sites on the other for each subject. Skin conductance amplitudes were 3.5 times larger at distal than medial sites (p less than .002), while skin conductance levels were 2.08 times larger at distal sites (p less than .0005). A significant Site X Stimulus interaction (p less than .025) indicated that the distal site was more sensitive to habituation over trials and to increases in skin conductance amplitudes with increasing stimulus intensity than the medial site. On the basis of these findings it is recommended that distal sites be used in preference to medial sites in the recording of skin conductance activity.

Adult↗
PubMed1991

Autonomic activity.

A review such as this can do no more than provide an indication of the issues involved in using autonomic activity as a means of providing a "window on the brain." Several points arise. One of the most important is that of careful and appropriate use of techniques available. One well-known textbook of experimental psychology published some time ago advocated the use of two dimes applied to the palm of the hand for the measurement of electrodermal activity. It was this sort of recommendation that led to the use of psychophysiological measurement falling into disrepute. As indicated in the second section, it is important to understand fully the peripheral mechanisms involved before measurement of electrodermal activity can be usefully carried out. Appropriate use of silver/silver chloride electrodes and physiologically appropriate levels of saline in the electrolyte medium can lead to accurate and repeatable measurement where artefact is not carelessly introduced. Equally important is the context in which studies are carried out. The psychological invasiveness of the technique is important to recognize, and it is here that measurement of autonomic activity probably scores over other methods that are available insofar as very little restriction of the subject is required and the number of transducers that must be applied is minimal. The measurement of autonomic activity within the totality of the experimental context is all important. As an example Dawson and Schell investigated the SCR to words which had previously been associated with shock. When these words were presented to the ear to which attention was not directed in a dichotic listening paradigm, an SCR could be elicited although the subject was unaware of the presentation of the stimulus. The importance of the Dawson and Schell study was the care that they took to make sure that the subject really was unaware of the critical stimulus and had not momentarily switched attention from the attended ear. More important, their experiment, in contrast to some which had gone before, used a balanced design in which the critical stimuli were presented on different occasions to each ear. As a result of this it was found that critical stimuli, which were presented to the left ear, right hemisphere, gave rise to SCRs, even when the subject was not aware of their presentation, whereas stimuli presented to the right ear, left hemisphere elicited no response.(ABSTRACT TRUNCATED AT 400 WORDS)

Autonomic Nervous System↗
PubMed1990

Relationships between central and autonomic measures of arousal at age 15 years and criminality at age 24 years.

Previous studies have indicated that criminality is in part genetically determined, but it is not clear how this predisposition manifests itself at a biological level. This prospective study tests the hypothesis that a psychophysiological predisposition to criminality partly manifests itself through autonomic and central nervous system underarousal. Psychophysiological measures, taken at the age of 15 years, were related to criminality status that was assessed at the age of 24 years. Criminals had a significantly lower resting heart rate, skin conductance activity, and more slow-frequency electroencephalographic activity than noncriminals. Differences were not mediated by social, demographic, and academic factors. These results constitute the first clear evidence that implicates underarousal in all three response systems (electrodermal, cardiovascular, and cortical) in the development of criminality. Although arousal variables correctly classified 74.7% of all subjects, psychophysiological factors alone cannot fully account for criminal behavior and do not negate the potential role of social variables in predicting criminal behavior.

Adolescent↗
PubMed1990

Evoked potential augmenting-reducing in psychopaths and criminals with impaired smooth-pursuit eye movements.

Previous studies that have assessed a stimulation-seeking theory of psychopathy are open to the criticism that psychopaths may lie on self-report questionnaires. The present study uses event-related potential (ERP) augmenting-reducing as a psychophysiological analog of stimulation-seeking in psychopaths to test this theory. It is also hypothesized that "schizoid" criminals, as defined by poor eye tracking, would show nonaugmenting/reducing, a profile characteristic of schizophrenia. Schizoid criminals were found to be characterized by nonaugmenting/reducing, but psychopaths were not found to be characterized by augmenting. It is concluded that stimulation-seeking is a viable theory of criminality but not of psychopathy, and that the etiological basis to schizoid criminality may differ substantially from criminality, per se.

Adult↗
PubMed1990

Relationships between N1, P300, and contingent negative variation recorded at age 15 and criminal behavior at age 24.

Recent event-related potential (ERP) studies indicate that antisocial and psychopathic behavior is in some circumstances characterized by heightened attentional processes. This prospective study assesses whether ERP measures of attention recorded in adolescence are capable of predicting criminality status in adulthood. N1, P300, and contingent negative variation (CNV) were recorded during a CNV paradigm in a representative sample of 101 male schoolchildren at age 15, and related to criminality status at age 24. Criminals-to-be were characterized by larger N1 amplitudes and faster P300 latencies to the warning stimulus. Psychopathic personality within the criminal group was associated with larger N1 and CNV amplitudes. A discriminant function analysis using N1 and P300 measures correctly classified 74% of cases. It is concluded that enhanced early attentional processing may be of etiological significance in the development of criminality and that ERP measures may be of value in the early prediction of criminal behavior.

Adolescent↗
PubMed1990

Autonomic orienting responses in 15-year-old male subjects and criminal behavior at age 24.

This prospective study analyzed relationships between skin conductance and heart rate measures of orienting in a noninstitutionalized sample of 101 15-year-old male subjects and criminal behavior as assessed at age 24 years. Subjects with a criminal record at age 24 (N = 17) had significantly smaller skin conductance responses and smaller heart rate deceleratory and acceleratory responses than the other subjects (N = 84). Lack of any skin conductance response was significantly more prevalent in subjects with a criminal record (31%) than in the control subjects (10%). These results implicate deficits in orienting with the later development of criminal behavior. The authors hypothesize that the genetic predisposition to criminal behavior may find its expression in part through smaller autonomic orienting.

Adolescent↗
PubMed1989

The Emanuel Miller memorial lecture 1987. Childhood markers for adult disorders.

The paper is concerned with examining some indices, measured in childhood, that may be considered to be "vulnerability" or "genetic" markers for later adult disorder. The disorders of prime interest in this instance are schizophrenia and criminality. The source of data for the paper is a longitudinal study carried out in Mauritius, which started in 1972 with the examination of a total population of 3-yr-olds. While these subjects are not yet at an age when a sufficient number have developed schizophrenia to allow definitive statements to be made, sufficient data are available to indicate that indices employed as markers at age 3 predict later patterns of behaviour that are in line with studies in the literature as being characteristic of those who later become schizophrenic. The age 3 index which is employed is hyper- or hypo-activity of the electrodermal system. Later work has made particular use of smooth pursuit eye-movement, which has become a particularly strong candidate as a genetic marker for schizophrenia. Also reported is material that suggests that electrodermal activity may also be used to predict later delinquent patterns of behaviour.

Arousal↗