Early handling, but not maternal separation, decreases emotional responses in two paradigms of fear without changes in mesolimbic dopamine

This study aimed at identifying the effects of neonatal handling (H) and maternal separation (MS) on two paradigms of fear, learned and innate, and on the tyrosine hydroxylase (TH) immunoreactive cells in adult life. Wistar rats were daily handled with a brief maternal separation, maternal separated for 3 h or left undisturbed during the first 10 days of life. Behavioural responses in the open-field (innate fear) and conditioned fear (learned fear) were evaluated. Moreover, a semi-quantitative analysis of TH immunoreactivity in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNpc) was performed using optical densitometry and confirmed by planar measurements of neuronal density. Early handling decreased behaviour responses of innate and learned fear in adult life, while maternal separation had no significant long-lasting effect on these responses compared to the non-handled group. The behavioural effects of early handling could not be explained by changes in the density of midbrain dopaminergic cells, which were not affected by handling or maternal separation.     

Verbal fluency dysfunction in euthymic bipolar patients: a controlled study

OBJECTIVE: To study the executive functioning in euthymic bipolar patients in comparison to healthy controls and to examine the relationship between neuropsychological deficits and clinical variables. METHODS: Twenty-five euthymic bipolar patients and 31 controls underwent a battery of executive tasks including mental flexibility, inhibitory control and verbal fluency tests. RESULTS: There were no significant differences between bipolar patients and controls in relation to mental flexibility and inhibitory control. However, patients performed worse than controls on verbal fluency tests. Poor performances on the Stroop Test and the Hayling and Brixton Tests--part A were associated to lifetime occurrence of psychotic symptoms, prior number of episodes, and previous hospitalizations. CONCLUSIONS: In our study, only verbal fluency tests differentiated bipolar euthymic patients from healthy controls. Patients who showed deficits in information processing speed and inhibitory control had more episodes and hospitalizations and lifetime occurrence of psychotic symptoms.     

Contextual recognition memory deficits in major depression are suppressed by cognitive support at encoding

Objectives

To investigate the effect of cognitive support (an associative orienting instruction at encoding) on contextual memory in depressed patients.

Methods

Seventeen patients (age 20-40 years, 14 women) diagnosed with major depressive disorder (MDD) and 22 healthy controls matched for age, gender and education completed a recognition memory task for item (object) and context (location), with or without an incidental binding cue at encoding. In addition, participants completed the vocabulary subtest of the Wechsler Adult Intelligence Scale (WAIS III) and the Wisconsin Card Sorting Test (WCST). Salivary samples were collected at 7 AM, 4 PM and 10 PM on the day of testing for cortisol and DHEA level measurement.

Results

Depressed patients showed a deficit in contextual memory in the absence of a binding cue but did not differ from healthy controls in item memory or when a binding cue was present. Cortisol and cortisol/DHEA ratios were lower in depressed patients compared to healthy controls and correlated with memory deficits.

Conclusions

Contextual memory deficits in MDD patients can be reduced by providing cognitive support at encoding.     

On the pitfalls of adjusting for gestational age at birth

Preterm delivery is a powerful predictor of newborn morbidity and mortality. Such problems are due to not only immaturity but also the pathologic factors (such as infection) that cause early delivery. The understanding of these underlying pathologic factors is incomplete at best. To the extent that unmeasured pathologies triggering preterm delivery also directly harm the fetus, they will confound the association of early delivery with neonatal outcomes. This, in turn, complicates studies of newborn outcomes more generally. When investigators analyze the association of risk factors with neonatal outcomes, adjustment for gestational age as a mediating variable will lead to bias. In the language of directed acyclic graphs, gestational age is a collider. The theoretical basis for colliders has been well described, and gestational age has recently been acknowledged as a possible collider. However, the impact of this problem, as well as its implications for perinatal research, has not been fully appreciated. The authors discuss the evidence for confounding and present simulations to explore how much bias is produced by adjustments for gestational age when estimating direct effects. Under plausible conditions, frank reversal of exposure-outcome associations can occur. When the purpose is causal inference, there are few settings in which adjustment for gestational age can be justified.     

Applying indigenous community-based participatory research principles to partnership development in health disparities research

This case study of community and university research partnerships utilizes previously developed principles for conducting research in the context of Native American communities to consider how partners understand and apply the principles in developing community-based participatory research partnerships to reduce health disparities. The 7 partnership projects are coordinated through a National Institutes of Health-funded center and involve a variety of tribal members, including both health care professionals and lay persons and native and nonnative university researchers. This article provides detailed examples of how these principles are applied to the projects and discusses the overarching and interrelated emergent themes of sharing power and building trust.