Central noradrenergic neurons: differential effects on body weight of electrolytic and 6-hydroxydopamine lesions in rats.

The ventral noradrenergic bundle (VB) of the rate brain has been proposed as the substrate for the hyperphagia and obesity produced by ventromedial hypothalamic lesions. To determine the relationship between body weight and damage to the VB, the effects of bilateral electrolytic and 6-hydroxy-dopamine (6-OHDA) lesions of the VB were compared. When rats were fed only a standard laboratory diet, no significant differences were found between groups. When a high-fat diet supplement was introduced, the group with electrolytic lesions became significantly heavier than the control group; however, the 6-OHDA group did not differ from the controls. Norepinephrine depletion was significantly greater following the 6-OHDA than the electrolytic lesions. Both lesions reduced telencephalic dopamine and serotonin only slightly. A second study in which both types of lesions were placed at a rostral ventromedial hypothalamic site yielded the same pattern of results. Diet-dependent increases in body weight were attributed to the destruction of a non-noradrenergic system, which was spared by the relatively selective 6-OHDA lesion but damaged by the nonselective electrolytic lesion.     

Reliability of DSM-IV anxiety and mood disorders: implications for the classification of emotional disorders

The reliability of current and lifetime Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) anxiety and mood disorders was examined in 362 outpatients who underwent 2 independent administrations of the Anxiety Disorders Interview Schedule for DSM-IV: Lifetime version (ADIS-IV-L). Good to excellent reliability was obtained for the majority of DSM-IV categories. For many disorders, a common source of unreliability was disagreements on whether constituent symptoms were sufficient in number, severity, or duration to meet. DSM-IV diagnostic criteria. These analyses also highlighted potential boundary problems for some disorders (e.g., generalized anxiety disorder and major depressive disorder). Analyses of ADIS-IV-L clinical ratings (0-8 scales) indicated favorable interrater agreement for the dimensional features of DSM-IV anxiety and mood disorders. The findings are discussed in regard to their implications for the classification of emotional disorders.     

Central catecholamine and peripheral noradrenaline depletion by 6-hydroxydopamine and active avoidance learning in rats

Three experiments are reported on the relation among catecholamine (CA) depletion, plasma corticosterone (11-OHCS) levels, and active aversive learning. A baseline study showed no significant relation beteen resting levels of 11-OHCS and central and/or peripheral CA depletion. On a two-way avoidance learning task, depletion of brain CAs produced a widespread learning deficit. When both central and peripheral CAs were depleted, only escape learning emerged. Similar effects occurred on a one-way task, but differences were not so marked. The findings are discussed in terms of a theory of CA-dependent cues.     

Eating disorders in a nonclinical adolescent population: implications for treatment

The present study investigates the prevalence of adolescent eating disorders across gender, cultural groupings, and socioeconomic status. The Eating Attitudes Test, the Binge-Eating Questionnaire, and a demographic questionnaire were administered to students at two high schools. The results indicate a high rate of eating disorders in a nonclinical adolescent population. The rates for binge eating are comparable to those found in studies of college students--found at a younger age. With regard to SES, cross-cultural and gender findings, it is clear that eating disorders cross socioeconomic class and ethnic groups, and have a higher rate of occurrence in males than previously reported. Given such high rates of eating problems in a nonclinical population, the issue of prevention and early detection must be addressed. Additionally, more specific information on male eating disorders is needed.     

Maternal styles in infant psychotherapy: Treatment and research implications

Infant psychotherapy, in which the mother is requested to follow the baby's activities without initiating or directing, is described. Mothers demonstrate different styles of involvement with their infants: a protective mode, a prohibitive mode, a competitive mode, and other ways of interfering with their infants' tendency to explore the environment. Attempts to analyze such factors as position, distance and movement are discussed. Research for recording and analyzing the movement of infant and mother dyads is proposed.     

Glutamate-hypothalamic-pituitary-adrenal axis interactions: implications for mood and anxiety disorders

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is a pathologic feature of certain mood and anxiety disorders that results in the increased production and secretion of corticotropin-releasing factor. There is increasing preclinical evidence that glutamate, an excitatory amino acid, plays an important role in the regulation of the HPA axis. Activation of glutamatergic projections to limbic structures such as the amygdala and brainstem structures such as the nucleus tractus solitarius is implicated in the stress response. There are laboratory and clinical suggestions that glutamatergic N-methyl-D-aspartate (NMDA) receptor antagonists function as antidepressants, and that chronic antidepressant treatments have a significant impact on NMDA receptor function. Clinical investigations of glutamate antagonists in patients with mood and anxiety disorders are in their infancy, with a few reports suggesting the presence of mood-elevating properties. Ultimately, HPA axis modulators, serotonin-enhancing agents, and glutamate antagonists might serve to increase neurotropic factors in key brain regions for affective and anxiety regulation, providing a putative final common pathway.     

The emergence of psychopathy: implications for the neuropsychological approach to developmental disorders

In this paper, I am going to examine the disorder of psychopathy and consider how genetic anomalies could give rise to the relatively specific neuro-cognitive impairments seen in individuals with this disorder. I will argue that genetic anomalies in psychopathy reduce the salience of punishment information (perhaps as a function of noradrenergic disturbance). I will argue that the ability of the amygdala to form the stimulus-punishment associations necessary for successful socialization is disrupted and that because of this, individuals with psychopathy do not learn to avoid actions that will harm others. It is noted that this model follows the neuropsychological approach to the study of developmental disorders, an approach that has been recently criticized. I will argue that these criticisms are less applicable to psychopathy. Indeed, animal work on the development of the neural systems necessary for emotion, does not support a constructivist approach with respect to affect. Importantly, such work indicates that while environmental effects can alter the responsiveness of the basic neural architecture mediating emotion, environmental effects do not construct this architecture. However, caveats to the neuropsychological approach with reference to this disorder are noted.     

Maternal behavior of spontaneously hypertensive and Wistar-Kyoto normotensive rats: effects of reciprocal cross-fostering of litters

Maternal behavior of spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) normotensive dams rearing either their natural pups or pups of the opposite strain was assessed when pups were 4-6 days of age. Consistent with previous reports, SHR dams caring for their natural pups were observed nursing and licking their pups more often than WKY dams and were away from their pups less often. The behavior of dams rearing cross-fostered pups demonstrated that this strain difference in patterns of maternal behavior is dependent on pup type. Mothers of both strains shifted their behavior in the direction of the opposite strain's maternal behavior pattern when caring for cross-fostered pups. This shift was most pronounced in SHR dams caring for WKY pups. These data suggest that alterations in patterns of maternal behavior produced by cross-fostering may play an important role in cross-fostering effects on the physiological development of SHRs previously reported.     

Diathesis-stress theories in the context of life stress research: implications for the depressive disorders.

Advances in the conceptualization and measurement of life stress in the past 2 decades raise several questions concerning traditional diathesis-stress theories of psychopathology. First, comprehensive measures of life stress force investigators to become more precise about the particular stressful circumstances hypothesized to interact with diatheses. Second, the influence of the diathesis on a person's life is typically ignored, which results in several types of possible bias in the assessment of life stress. Finally, information is available on diatheses and stress for specific disorders to provide a foundation for more empirically based hypotheses about diathesis-stress interactions. This possibility is outlined for depression. Such an approach provides the basis for developing broader, yet more specific, frameworks for investigating diathesis-stress theories of psychopathology in general and of depression in particular.     

Maternal separation alters later consumption of novel liquids in the squirrel monkey

The consumption of novel, fruit-flavored drinks was measured in juvenile squirrel monkeys that had either had their mother removed from the home cage for 2 h on 80 occasions prior to weaning or had not undergone this separation procedure. Among previously separated animals, males drank more than did females during the first 30 min following presentation, whereas there was no difference in the drinking of nonseparated males and females at this time. Further, the amount of liquid consumed during the 20 h following presentation increased across days of exposure in the nonseparated, but not in the previously separated monkeys. These results show that brief maternal separation can affect the later behavior of squirrel monkeys, and are consistent with findings in rhesus macaques that maternal separation alters later exploratory behavior.     

Outcome and epidemiological research on personality disorders: implications for classification

The construct of personality disorder has an overall definition that describes chronicity. However, the findings of outcome research indicate that while many patients stop meeting criteria for specific categories of disorder over time, they often continue to suffer from dysfunctional traits. One can also interpret epidemiological findings on personality disorders as overestimating disorders due to a failure to distinguish them from traits. Taken together, these findings point to the need for a revision of the classification of personality disorders that would separate enduring traits from reversible symptoms.     

Temperament and its implications for neuroimaging of anxiety disorders

We review the attributes of inhibited and uninhibited infant temperaments, and their developmental trajectories into early adulthood. Inborn individual differences in infants' propensity to respond to novel people and objects are associated with persistent differences in the responsivity of the amygdala to novelty, as measured with functional magnetic resonance imaging, after more than 20 years of development. Because an inhibited temperament is a risk factor for developing later psychiatric disorders, particularly generalized social anxiety disorder, temperamental differences are confounds in neuroimaging and genetic studies. Longitudinal studies are a unique tool for understanding the developmental and temperamental risk factors for psychiatric disorder.     

Complexity effects in visuo-spatial working memory: implications for the role of long-term memory

Several studies have shown that the capacity of visuo-spatial working memory is limited by complexity. Using a variant of the Corsi blocks task, this paper investigates the effect of complexity of the to-be-remembered path on visuo-spatial memory span. Redundancy was determined by three Gestalt principles: symmetry, repetition, and continuation. Experiment 1 revealed an effect of path complexity. The subsequent experiments explored whether the superiority for recall of structured over complex paths can be attributed solely to the operation of visuo-spatial working memory, or whether it also reflects the use of long-term knowledge. Experiment 2 demonstrated that the effect of complexity remained, even when the mechanisms for visuo-spatial coding were removed by a secondary visuo-spatial task. In Experiments 3 and 4 subjects were trained in the recall of complex paths. This led to the creation of long-term memory representations for these paths, as shown by an improvement in their span, and a concomitant lack of transfer to new paths. Finally, Experiment 5 showed that one prior repetition of a complex path was sufficient to produce specific and long-term learning effects. These results point to the involvement of long-term memory processes in the temporary retention of visuo-spatial material for which representations exist in long-term memory. They also suggest that the effect of complexity may provide a tractable technique for investigating the mechanisms underlying the limits of visuo-spatial short-term storage.     

Specific-token effects in screening tasks: possible implications for aviation security

Screeners at airport security checkpoints perform an important categorization task in which they search for threat items in complex x-ray images. But little is known about how the processes of categorization stand up to visual complexity. The authors filled this research gap with screening tasks in which participants searched for members of target categories in visual displays. The authors found that when targets were sampled with replacement and repetition, participant screeners relied on recognizing familiar targets and had great difficulty using category-general knowledge. The authors observed a "heartbeat" in detection performance--it improved while test images repeated but dropped sharply when unfamiliar targets from the same categories appeared. This reliance on familiarity illuminates the processes of categorization under conditions of visual complexity and suggests limits on those processes. This reliance also has implications for the training and evaluation of screeners in the field.     

Placebo effects in developmental disabilities: implications for research and practice

Recent clinical trials of secretin in children with autism showed robust placebo effects and no benefit of secretin over placebo. This article explores the reasons for the observed placebo effects, focusing on the heightening of positive expectancy by media attention and by the sensory experiences associated with intravenous injections. Comparisons are drawn with research involving other novel treatments and other clinical populations of children with developmental disabilities and neurobehavioral disorders. Research regarding mechanisms of placebo effects is reviewed, including patient and clinician attributes, expectancy effects, participation effects, changes in caregiver behavior, and conditioning. New evidence regarding the biological basis of placebo effects is briefly presented. Since placebo effects are ubiquitous and may operate by a variety of mechanisms, research design is critical in designing clinical trials and in evaluating other outcomes research. Measurement issues important for research in developmental disabilities are emphasized. Ethical concerns have been raised regarding the use of placebo in clinical research, but current analysis suggests that placebo controls are necessary and defensible on ethical grounds, if certain conditions are met. The study of placebo effects ("placebology") holds great promise as a new area of research in therapeutics. The author's research in the potential augmentation of stimulant effects in children with attention deficit/hyperactivity disorder (ADHD) by adding placebo in open label is briefly presented. The placebo has always been integral to the practice of medicine, but advances in scientific medicine and medical ethics have diminished the role and use of placebo in practice. An innovative approach to the ethical use of placebo is proposed.     

Concreteness effects in different tasks: implications for models of short-term memory

This study investigates concreteness effects in tasks requiring short-term retention. Concreteness effects were assessed in serial recall, matching span, order reconstruction, and free recall. Each task was carried out both in a control condition and under articulatory suppression. Our results show no dissociation between tasks that do and do not require spoken output. This argues against the redintegration hypothesis according to which lexical-semantic effects in short-term memory arise only at the point of production. In contrast, concreteness effects were modulated by task demands that stressed retention of item versus order information. Concreteness effects were stronger in free recall than in serial recall. Suppression, which weakens phonological representations, enhanced the concreteness effect with item scoring. In a matching task, positive effects of concreteness occurred with open sets but not with closed sets of words. Finally, concreteness effects reversed when the task asked only for recall of word positions (as in the matching task), when phonological representations were weak (because of suppression), and when lexical semantic representations overactivated (because of closed sets). We interpret these results as consistent with a model where phonological representations are crucial for the retention of order, while lexical-semantic representations support maintenance of item identity in both input and output buffers.     

Maternal stress and pituitary-adrenal manipulations during pregnancy in rats: effects on morphology and sexual behavior of male offspring.

The purpose of the present study was to determine whether the demasculinizing and feminizing effects of prenatal stress (i.e., stress applied to the mother during pregnancy) in rats reported previously are mediated by activation of the maternal pituitary-adrenal axis. Neither whole-body restraint, with or without hyperthermia, nor ACTH treatment during the last third of gestation had any reliable effect on masculine or feminine sexual behavior in male Sprague-Dawley offspring, although these treatments produced maternal pathology and evidence of maternal adrenocorticoid release. Significant littermate similarity was found for almost every morphological and behavioral measure. Failure to control for the litter variable may account for many previously reported effects of prenatal stress on sexual behavior in rats. The discrepancy between the present and earlier findings is discussed in terms of methodological and theoretical considerations.