Complete recovery of olfactory associative learning by activation of 5-HT4 receptors after dentate granule cell damage in rats

Bilateral intradentate injections of 3.0 μg of colchicine induced a substantial loss of granule cells and damage to the overlying pyramidal cell layer in region CA1 in adult male Long-Evans rats. All rats with such lesions showed a significant associative learning deficit in an olfactory discrimination task, while being unimpaired in the procedural component of this task. Injection of a partial selective 5-HT₄ agonist (SL65.0155; 0.01 mg/kg, i.p., vs. saline) before the third of six training sessions enabled complete recovery of associative learning performance in the lesioned rats. Activation of 5-HT₄ receptors by a selective agonist such as SL65.0155 might therefore provide an opportunity to reduce learning and memory deficits associated with temporal lobe damage, and could be useful for the symptomatic treatment of memory dysfunctions related to pathological aging such as Alzheimer’s disease.     

The Role of Rumination in Predicting Seasonality

The impact of the changing seasons on mood and behavior (i.e., seasonality) has long been of interest to researchers. Recently, researchers have begun to look beyond biological explanations to investigate psychological variables that may play a role in the development of seasonal affective disorder (SAD) and subsyndromal (S-SAD) levels of seasonality. Rumination, in particular, has received initial support as a process that predicts more severe levels of winter depression. In the first study, we assessed the effects of rumination, current weather conditions, current level of depression, and attitudes toward weather conditions as predictors of seasonality. In addition to weather conditions, weather attitudes, and current depression, rumination emerged as a significant predictor of seasonality in females but not for males. In the second study, we followed individuals categorized as being high (S-SAD) and low in seasonality over time and assessed for depression at Time 1 and Time 2. Rumination, in addition to current weather conditions and weather attitudes, emerged as a significant predictor of depression for females in the S-SAD group. The results of these studies provide support for the role of rumination in seasonal depression, particularly for females. This type of research may contribute to attempts to better explain gender differences in seasonal depression.     

Anterior but not intralaminar thalamic nuclei support allocentric spatial memory

Medial thalamic damage is a common cause of severe memory disruption in humans. Both the anterior thalamic nuclei (ATN) and the intralaminar thalamic nuclei (ILN) have been suggested as primary sites of diencephalic injury underlying learning and memory deficits, but their respective roles have yet to be resolved. The present study explicitly compared two spatial memory tasks in male PVGc hooded rats with selective neurotoxic lesions to either (1) the ATN or (2) the rostral ILN (and adjacent lateral mediodorsal thalamic nuclei; ILN/LT lesions). As predicted, the ATN group, but not the ILN/LT group, exhibited clear deficits in the Morris water maze task for the initial acquisition of a fixed hidden platform and its reversal to a new position. The second task examined acquisition of egocentric spatial reference memory for a left or right body turn, using any three arms in an 8-arm water maze on any given trial; contrary to predictions, both lesion groups performed as well as the Sham group. The lack of deficits in ILN/LT rats on this second task contrasted with previous findings reporting a detrimental effect of ILN/LT lesions on egocentric working memory. The clear dissociation between the influence of ATN and ILN/LT lesions with respect to allocentric spatial reference memory in the Morris maze emphasizes that caution is required when interpreting the effects of non-ATN thalamic lesions on spatial memory when the lesions encroach substantial areas of the adjacent ATN region.     

I. Genotype-environment interaction in the schizophrenia spectrum: genetic liability and global family ratings in the Finnish Adoption Study

In the Finnish Adoption Study, a national sample of adoptees with high versus low genetic liability for schizophrenia spectrum disorders was indexed by DSM-III-R diagnoses of their biological, adopting-away mothers. The rearing-family environments of the adoptees were independently evaluated from global ratings of directly observed adoptive family relationships. The interaction of high genetic liability and dysfunction of the rearing families predicted highly significantly to schizophrenia spectrum disorder of the adoptees at 21-year follow-up. Either low genetic liability or healthy rearing protected against a spectrum outcomes for the adoptees. Initial adoptive parent diagnosis, as a proxy for rearing family dysfunction, predicted to adoptee outcome only as a trend.     

II. Genotype-environment interaction in the schizophrenia spectrum: qualitative observations

Previous reports from the Finnish Adoptive Family Study of Schizophrenia have documented significant interplay between genetics (G) and family rearing (E), leading to adoptee outcomes of schizophrenia spectrum disorders. Quantitative evidence for this interplay is significantly enhanced when both high genetic liability and severe environmental dysfunction are present. However, when either genetic liability is low or the rearing environment is healthy, the adoptees appear to be resiliently protected against a pathologic outcome. Nevertheless, exceptions to this pattern do occur. Six qualitative vignettes, together with quantitative measures and categorical diagnoses from the same families, illustrate how multiple methods partially confirm one another and also suggest where further exploration of gene-environment interaction is needed.     

Differences and similarities in event recall and suggestibility between children and adults in Germany and the United States

Children (5-6 year olds, 7-8 year olds, 9-10 year olds) and adults from Germany and the United States were shown a brief video of a theft. One week later, participants were asked to give a free narrative of an observed event (free recall), followed either by sets of misleading or unbiased questions, and finally they were given a three-choice recognition question for each queried item. German participants of all ages had higher levels of correct free recall than did American participants. American adults and 9-10 year olds gave more correct responses to the open-ended unbiased questions than did their German counterparts. Germans of all ages made more correct responses to the misleading questions, whereas national differences, favoring the Germans, for incorrect response to misleading questions were restricted to the 5-6 year olds. National differences were interpreted as reflecting possible differences in strategic abilities, exposure to formal instruction, and the degree to which children experience self-directed, autonomous learning opportunities.     

Early maladaptive schemas in Finnish adult chronic pain patients and a control sample

Engel (1959) suggested that negative physical or emotional experiences in childhood predispose to the development of chronic pain. Studies have shown that physical and sexual abuse in early life is connected with chronic pain. Emotional adversities are much less studied causes contributing to the development of chronic pain and disability. Early emotional abuse, neglect, maltreatment and other adversities are deleterious childhood experiences which, according to Young's schema theory (1990), produce early maladaptive schemas (EMSs). The primary goal of this study was to examine whether early adversities were more common in chronic pain patients than in a control group. A total of 271 (53% women) first-visit chronic pain patients and 331 (86% women) control participants took part in the study. Their socio-demographic data, pain variables and pain disability were measured. To estimate EMSs the Young Schema Questionnaire was used. Chronic pain patients scored higher EMSs reflecting incapacity to perform independently, catastrophic beliefs and pessimism. The most severely disabled chronic pain patients showed an increase in all the EMSs in the Disconnection and Rejection schema domain, namely Abandonment/Instability, Mistrust/Abuse, Emotional Deprivation, Defectiveness/Shame and Social Isolation/Alienation EMSs. The results of the study suggested that chronic pain patients had suffered early emotional maltreatment.