Effects of neonatal forebrain noradrenaline depletion on recovery from brain damage: performance on a spatial navigation task as a function of age of surgery and postsurgical housing

The experiments examined the contributions of forebrain noradrenaline and environmental enrichment to recovery of place navigation ability in rats after hemidecortication in infancy or adulthood. Noradrenaline depletion did not affect recovery from neonatal hemidecortication, although the early hemidecortications did allow sparing of function relative to adult operates. Noradrenaline depletion also failed to attenuate the positive effects of enriched housing on otherwise normal rats. Noradrenaline depletion did retard recovery of adult hemidecorticate rats housed in standard laboratory cages, but it did not retard recovery of adult hemidecorticate rats housed in enriched environments. The results suggest that noradrenaline is importantly involved in enhancing recovery from brain damage when other sources of compensation (e.g., neonatal injury, enriched environment) are absent.     

Retrospective coding in pigeons' delayed matching-to-sample

In this study we examined how coding processes in pigeons' delayed matching-to-sample were affected by the stimuli to be remembered. In Experiment 1, two groups of pigeons initially learned 0-delay matching-to-sample with identical comparison stimuli (vertical and horizontal lines) but with different sample stimuli (red and green hues or vertical and horizontal lines). Longer delays were then introduced between sample offset and comparison onset to assess whether pigeons were prospectively coding the same events (viz., the correct line comparisons) or retrospectively coding different events (viz., their respective sample stimuli). The hue-sample group matched more accurately and showed a slower rate of forgetting than the line-sample group. In Experiment 2, pigeons were trained with either hues or lines as both sample and comparison stimuli, or with hue samples and line comparisons or vice versa. Subsequent delay tests revealed that the hue-sample groups remembered more accurately and generally showed slower rates of forgetting than the line-sample groups. Comparison dimension had little or no effect on performance. Together, these data suggest that pigeons retrospectively code the samples in delayed matching-to-sample.     

Categorical shape and color coding by pigeons

Categorical coding is the tendency to respond similarly to discriminated stimuli. Past research indicates that pigeons can categorize colors according to at least three spectral regions. Two present experiments assessed the categorical coding of shapes and the existence of a higher order color category (all colors). Pigeons were trained on two independent tasks (matching-to-sample, and oddity-from-sample). One task involved red and a plus sign, the other a circle and green. On test trials one of the two comparison stimuli from one task was replaced by one of the stimuli from the other task. Differential performance based on which of the two stimuli from the other task was introduced suggested categorical coding rules. In Experiment 1 evidence for the categorical coding of sample shapes was found. Categorical color coding was also found; however, it was the comparison stimuli rather than the samples that were categorically coded. Experiment 2 replicated the categorical shape sample effect and ruled out the possibility that the particular colors used were responsible for the categorical coding of comparison stimuli. Overall, the results indicate that pigeons can develop categorical rules involving shapes and colors and that the color categories can be hierarchical.     

Sex differences in the effects of gonadectomy on amphetamine-induced rotational behavior in rats

The effects of gonadectomy on amphetamine-induced rotational behavior were studied in male and female rats. Different systemic doses were used to produce equivalent brain concentrations of the drug in each group, thereby controlling for sex differences in the metabolism of amphetamine. Ovariectomy of female rats significantly attenuated amphetamine-induced rotation, whereas castration of males was without effect. The results support the idea that in females, the endogenous gonadal hormones facilitate functional activity in the mesostriatal dopamine system.     

Quality-of-life measures: hospital interview versus home questionnaire

Measures adapted from social survey research were used to assess the quality of life of 33 end-stage renal disease (ESRD) patients in a 2-week test-retest design that varied both location and format of administration (hospital interview vs. home self-administered questionnaire). The measures were found to have substantial consistency over time, location, and format. These results indicate that quality of life is a stable construct and support the usefulness of questionnaire quality-of-life measures for evaluating medical interventions.     

Stress and coping in early adolescence: relationships to substance use in urban school samples

Measures of stress and coping were obtained from two cohorts of urban adolescents during the seventh- to eighth-grade period and were related to indices of cigarette smoking and alcohol use. Predictions were derived from a stress coping model of substance use. Stress was indexed by measures of subjective stress, recent events, and major life events; coping was assessed by behavior-based and intention-based methods. Concurrent and prospective analyses were consistent with predictions, indicating that stress was positively related to substance use, and four coping mechanisms (behavioral coping, cognitive coping, adult social support, and relaxation) were inversely related to substance use. Two types of predicted interactions, Stress X Coping and Positive X Negative Events, were found. Measures indexing peer support, distraction coping, and aggressive coping were positively related to substance use, independent of other predictors. Implications for substance use theory and prevention research are discussed.     

Health as a value: methodological and theoretical considerations

The concept of value placed on health is very important in several different theoretical approaches to the study of health behavior. In practice, however, health value is generally assumed to be universally high rather than being directly measured. If this assumption is incorrect, then theories that include health value have rarely been adequately tested. This paper presents a short 4-item Likert scale designed to measure the value placed on health. Norms from the utilization of this scale in five different samples are presented. Health value is found to increase with age among girls, but the increase apparently stops by late adolescence, before full adult levels of health value are achieved. Middle-aged women place a higher value on health than do middle-aged men, although no comparable sex difference appears in a sample of undergraduates. Consistent with theoretical predictions, both health locus of control beliefs and beliefs in the efficacy of certain preventive health behaviors correlate more highly with the performance of those same behaviors 5 to 9 months later among respondents who place a high value of health relative to those who do not value health so highly. However, this interaction is found only when it can be safely assumed that health is the primary value underlying the behavior. The importance of considering a variety of values in addition to health as possible motivators of preventive health behavior is stressed.     

Psychopathy: A psychobiological perspective

After critically examining the concept of psychopathy and reviewing the major existing theories of psychopathy in the light of a psychobiological conception of abnormal behaviour (Öhman, 1981), this paper attempts to present an integrated, psychobiological model of psychopathy. Essentially this analyses psychopathy in terms of the predisposing influences, the triggering environmental events which initiate psychopathic behaviour, and the neurophsychological mechanisms which mediate it. It is suggested that individuals who show chronic antisocial behaviour, conforming to the North American term ‘sociopath’, may demonstrate a maturational deficit but do not necessarily show a psychopathic personality disorder. The latter is said to be characterised, at a personality trait level, by high Impulsiveness and Psychopathy (Blackburn, 1982 a, b), reflecting interactive deficits in goal direction and affect. At a dynamic (state) level, a psychopathic personality disorder is said to be characterised by a lack of coping, reflecting either, in the case of the secondary psychopath, a deficit in primary appraisal, (over-perception of threat), or in the case of the primary psychopath, a deficit in secondary appraisal (low perceived control over aversive environmental events). It is further suggested that a genetic predisposition to social withdrawal and exposure to an uncontrollably aversive early environment may interact to predispose an individual to develop a psychopathic personality disorder in adulthood.