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Biomedical subjects

D C Fowles

Publications and source records attributed to D C Fowles.

At least 19 recordsLinked to original sources
PubMed2000

Electrodermal hyporeactivity and antisocial behavior: does anxiety mediate the relationship?

Electrodermal hyporeactivity in the anticipation of aversive stimuli is a highly reliable correlate of diagnosed psychopathy and undersocialized aggressive conduct disorder (UACD), and it has been interpreted as reflecting a weak behavioral inhibition system (BIS) as conceptualized in Gray's work (e.g., in: Royce, J.R. (Ed.), Multivariate Analysis and Psychological Theory. Academic Press, New York, NY, p. 409, 1973). This interpretation predicts that electrodermal hyporeactivity should be associated with a single dimension of temperament involving both low anxiety and behavioral disinhibition. However, temperament scales identify separate dimensions of trait anxiety/neuroticism and inhibitory control, and most investigators have assumed that the BIS is associated with the trait anxiety/neuroticism dimension. The present review supports the view that electrodermal hyporeactivity is associated with both low anxiety and disinhibition, as expected, and, possibly, with poor control of emotional expression. Additionally, electrodermal hyporeactivity appears to relate to an impulsivity dimension among psychopaths rather than to the core personality features of psychopathy. Recent findings raise the possibility that psychopaths suffer from a broader deficit (sometimes described as an executive function deficit) than a weak BIS and that electrodermal hyporeactivity might relate to this broader deficit. It is proposed that problems with impulsivity are more strongly documented than the broader concept of executive function deficits and that a primary disinhibition can produce secondary executive function deficits. A disinhibitory deficit is consistent with the weak BIS hypothesis. Overall, the results appear to be consistent with the electrodermal hyporeactivity-weak BIS hypothesis, but many issues remain to be resolved.

Antisocial Personality Disorder↗
PubMed2000

Electrodermal activity and temperament in preschool children.

This study had two objectives: To examine poorly understood patterns of young children's electrodermal reactivity and to test the hypothesis that this reactivity reflects individual differences in the behavioral inhibition system (BIS). We recorded skin conductance responses (SCRs) from 92 4-year-old children during a laboratory session that encompassed physiological and psychological stimuli. Physiological stimuli (breaths), moderately loud to loud sounds (expected and unexpected) and, to a lesser extent, stimuli with psychological significance elicited clear SCRs. Induction of psychological conflict and exposure to emotional film clips for the most part did not elicit increases in skin conductance (SC). Children's temperament dimensions of fearfulness and effortful (or inhibitory) control--two components of the BIS--were assessed using robust observational batteries at age 2 and 4 years. The theoretically expected correlations between overall SC lability (reflecting SC levels) and both dimensions of temperament were significant, albeit modest and limited to the contemporaneous measures at age 4.

Arousal↗
PubMed2000

Temperament as a moderator of pathways to conscience in children: the contribution of electrodermal activity.

A longitudinal study (G. K. Kochanska, 1997) showed that temperamental fearfulness, assessed at toddler age via observational data and maternal ratings, moderated pathways to internalized conscience at age 4. For fearful children, maternal gentle discipline deemphasizing power predicted conscience development; for fearless children, attachment security predicted conscience development. Electrodermal reactivity assessed at age 4 on the same children was used as a physiological reflection of fearful temperament and was substituted for the earlier fearfulness measure to test the theoretical model. As expected, for electrodermally reactive children, maternal gentle discipline predicted conscience, whereas for nonreactive children, attachment security predicted conscience. The findings support the notions of (a) electrodermal reactivity at an early age as a correlate of temperament, (b) temperament as a moderator of socialization in early moral development, and (c) lovelessness in psychopathic individuals as an index of the failure of the alternative pathway (via attachment) to conscience in fearless children.

Arousal↗
PubMed1992

No evidence of classical conditioning of electrodermal responses during anesthesia.

Classical conditioning of skin conductance responses was studied in 26 healthy volunteers and 31 patients who received general anesthesia (0.5 MAC isoflurane-70% nitrous oxide) for minor gynecologic surgery to determine whether there was autonomic evidence of new learning during anesthesia. In the conditioning phase, a loud noise was paired with a target word (conditioned stimulus [CS]). Conditioning was established if the CS produced conditioned responses, i.e., greater skin conductance responses than other, "filler words." In the subsequent elicitation phase, we investigated whether it was possible to elicit similar conditioned responses to the CS when it was presented without noise about 3 h later. Conditioning was established in the control group, who received no anesthesia. There were differences in response magnitudes of 0.32 and 0.27 mu siemen between responses to the CS and filler words, P less than 0.001. In contrast, there was no evidence that conditioning was established during anesthesia. In the elicitation phase, conditioned responses to the CS could be elicited in volunteers; i.e., response magnitudes were greater for the CS than other words (during the first two blocks of trials), with differences of 0.19 to 0.48 mu siemen, P less than 0.05 to P less than 0.001. In contrast, responses to the CS could not be elicited in patients after anesthesia. There was also no evidence of recognition of words that were presented during anesthesia in patients, but recognition was manifested in volunteers. Thus, in contrast to our previous demonstration of conditioning in subjects who received 30% nitrous oxide in oxygen, there was no evidence of conditioning in anesthetized patients.

Adult↗
PubMed1987

Effects of a subanesthetic concentration of nitrous oxide on establishment, elicitation, and semantic and phonemic generalization of classically conditioned skin conductance responses.

Classical conditioning of skin conductance responses was studied in 16 men and 16 women breathing 30% nitrous oxide or 100% oxygen to see how nitrous oxide affected establishment, elicitation, and generalization of conditioned responses (CRs). For CRs that had been established before gas inhalation, nitrous oxide blocked elicitation of "anticipatory" (long latency) but not "orienting" (short latency) CRs. Nitrous oxide appeared to prevent new CRs from being established during its inhalation, but learning evidently took place since anticipatory CRs could be elicited after nitrous oxide inhalation had ceased. Words were used as the conditioned stimuli and nitrous oxide altered generalization of CRs to other words related in meaning or sound, though generalization effects were limited. Nitrous oxide also seemed to reduce the efficacy of the unconditioned stimulus. The results were interpreted in terms of Rescorla's theory of classical conditioning.

Adult↗
PubMed1985

Electrodermal potential and conductance measurements clinically discriminate between cystic fibrosis and control patients.

To evaluate the adaptation of electrodermal techniques for cystic fibrosis screening, skin surface bioelectric measurements were recorded from 37 established cystic fibrosis patients, 45 asthmatic patients, and 10 normal controls, ranging in age from 6 to 22 yr. Six skin potential and six skin conductance measures of sweat gland activity without the collection of sweat distinguished between the cystic fibrosis, normal, and asthmatic groups (F ratios greater than 10.0; p less than 0.0001). Discriminant analysis using the two best electrodermal measures (the mean of five preresponse potential levels and the mean of five preresponse conductance levels for each subject) to assign experimental group membership matched actual group membership with 92.7% accuracy. We believe these results warrant further investigation of electrodermal procedures as a direct, simple, yet noninvasive means of screening for cystic fibrosis.

Adolescent↗