Developmental study of multiple memory stages in the cuttlefish, Sepia officinalis

The inhibition of predatory behavior observed during the "prawn-in-the-tube" procedure has been extensively used in studies of cuttlefish learning. The present study examines the effect of age on the conditioning of this response in the cuttlefish, Sepia officinalis. Data show that a significant increase in acquisition performance occurs between 15 and 21 days of age. The retention curves in 8- and 15-day-old cuttlefish show a monotonic memory process, presumably reflecting the presence of only short-term memory. In 21-day-old cuttlefish, there are two distinct processes which could be a labile short-term memory, and a subsequent intermediate memory. These mnesic systems seem to become more effective over the course of post-embryonic development. Moreover, the retention curves obtained in the oldest cuttlefish (30- and 90-day-old) bear a close resemblance to that observed in adults. These behavioral findings will allow further work on the cellular and molecular mechanisms of learning and memory in the cuttlefish.     

Suicide in bipolar disorder: Risks and management

Bipolar disorders are prevalent, often severe, and disabling illnesses with elevated lethality largely due to suicide. Suicide rates average approximately 1% annually, or perhaps 60 times higher than the international population rate of 0.015% annually. Suicidal acts typically occur early in bipolar disorders and in association with severe depressive or mixed states. The high lethality of suicidal acts in bipolar disorders is suggested by a much lower ratio of attempts:suicide (approximately 3:1) than in the general population (approximately 30:1). Risk factors can help to identify patients at increased suicidal risk, but ongoing clinical assessment is essential to limit risk. Empirical short-term interventions to manage acute suicidal risk include close clinical supervision, rapid hospitalization, and electroconvulsive therapy. Remarkably, however, evidence of the long-term effectiveness of most treatments against suicidal behavior is rare. A notable exception is lithium prophylaxis, which is associated with consistent evidence of major (approximately 80%), sustained relative reductions of risk of suicides and attempts, and lower lethality (increased attempts:suicide ratio). Such benefits are unproved for other treatments commonly used to treat bipolar disorder patients, including anticonvulsants, antipsychotics, antidepressants, and psychosocial interventions. Applying available knowledge systematically, with close and sustained clinical supervision, can enhance management of suicidal risk in bipolar disorders patients.     

Testing differences between nested covariance structure models: Power analysis and null hypotheses

For comparing nested covariance structure models, the standard procedure is the likelihood ratio test of the difference in fit, where the null hypothesis is that the models fit identically in the population. A procedure for determining statistical power of this test is presented where effect size is based on a specified difference in overall fit of the models. A modification of the standard null hypothesis of zero difference in fit is proposed allowing for testing an interval hypothesis that the difference in fit between models is small, rather than zero. These developments are combined yielding a procedure for estimating power of a test of a null hypothesis of small difference in fit versus an alternative hypothesis of larger difference.     

The development of a Spanish language version of the Worn Out scale of the General Well-Being Questionnaire (GWBQ)

The paper describes the development of a short Spanish-language version of the General Well-Being Questionnaire (GWBQ; Cox and Gotts, 1987), based on the 12 items of its Worn Out scale. Research has shown the English-version Worn Out scale to be sensitive to aspects of the design and management of work. This study aimed to test its cross-cultural consistency in a Spanish-language workplace context. The data were collected from a sample of 229 workers in Valencia (Spain). Confirmatory Factor Analyses showed the factorial validity, reliability, and concurrent validity of the new Spanish version to be adequate. The sensitivity of the new measure to safety behavior and the reporting of accidents was also assessed and shown to be good. The new questionnaire extends the usefulness of the parent questionnaire to occupational health psychology research in the Spanish language by offering a short assessment tool appropriate for workplace studies.     

Neurocognitive dysfunction in children with sleep disorders

It is well known that adults with sleep disturbances frequently exhibit a wide range of neurocognitive decrements, and that these deficits are potentially reversible with effective treatment. However, the consequences of respiratory sleep disturbances on neurocognitive function in children have only recently been evaluated, and suggest a strong causal association between the episodic hypoxia and sleep fragmentation that characterize the disease and the emergence of reduced memory, attention and intelligence as well as a link to problematic and hyperactive behaviours and mood disturbances. This article takes a critical look at the current literature on these issues, reviews the major findings and discusses such findings in conjunction with those derived from pertinent animal models.     

Experiments on the emergence of human communication

Children learn language from their parents and then use the acquired system throughout the rest of their life with little change. At least that is commonly assumed. But a recent paper by Galantucci adds to the growing evidence that adults (and children) are able to create and negotiate complex communication systems from scratch and relatively quickly, without a prior model. This raises questions of what cognitive mechanisms are implied in this joint construction of communication systems, and what the implications are for the origins of human language.     

The adrenergic receptor α-2A gene (ADRA2A) and neuropsychological executive functions as putative endophenotypes for childhood ADHD

There is resurgent interest in the psychiatric literature in endophenotypes, variables thought to more strongly reflect the effects of candidate genes than do manifest disorders. In a sample of 176 children with attention deficit hyperactivity disorder (ADHD) and 52 of their siblings, we examined the validity of several putative endophenotypes for ADHD that represent commonly used clinical measures of multiple cognitive/neuropsychological domains of executive functions (EFs). We review their distributional normality, their relations to ADHD symptoms in probands and unaffected siblings relative to nonADHD controls, and their correlation in siblings. We also tested the EF measures’ associations with the ADRA2A gene and whether they mediated or moderated the associations between ADHD and ADRA2A. Several EF measures showed association with ADRA2A, as well as moderation, but not mediation, of its association with ADHD. Implications of the results for evaluating the validity and utility of putative endophenotype measures and for finding candidate gene effects on ADHD are discussed.