Neurosteroids in the Hippocampus: Neuronal Plasticity and Memory

The hippocampus, which is critically involved in learning and memory processes, is known to be a target for the neuromodulatory actions of steroid hormones produced by the adrenal glands and gonads. Much of the work of B.S. McEwen and collaborators has focused on the role of glucocorticosteroids and estrogen in modulating hippocampal plasticity and functions. In addition to hormones derived from the endocrine glands, cells in the hippocampus may be exposed to locally synthesized neurosteroids, including pregnenolone, dehydroepiandrosterone and their sulfated esters as well as progesterone and its reduced metabolites. In contrast to hormones derived from the circulation, neurosteroids have paracrine and/or autocrine activities. In the hippocampus, they have been shown to have trophic effects on neurons and glial cells and to modulate the activity of a variety of neurotransmitter receptors and ion channels, including type A gamma-aminobutyric acid, N-methyl-D-aspartate and sigma receptors and N- and L-type Ca2+ channels. There is accumulating evidence that some neurosteroids, in particular pregnenolone sulfate, have strong influences on learning and memory processes, most likely by regulating neurotransmission in the hippocampus. However, the hippocampus is not the only target for the mnesic effects of neurosteroids. Associated brain regions, the basal nuclei of the forebrain and the amygdaloid complex, are also involved. Some neurosteroids may thus be beneficial for treating age- or disease-related cognitive impairments.     

Using segmented linear regression models with unknown change points to analyze strategy shifts in cognitive tasks

Some years ago, Beem (1993, 1995) described a program for fitting two regression lines with an unknown change point (Segcurve). He suggested that such models are useful for the analysis of a variety of phenomena and gave an example of an application to the study of strategy shifts in a mental rotation task. This technique has also proven to be very fruitful for investigating strategy use and strategy shifts in other cognitive tasks. Recently, Beem (1999) developed SegcurvN, which fitsn regression lines with (n - 1) unknown change points. In the present article we present this new technique and demonstrate the usefulness of a three-phase segmented linear regression model for the identification of strategies and strategy shifts in cognitive tasks by applying it to data from a numerosity judgment experiment. The advantages and shortcomings of this technique are evaluated.     

A program for fitting two-phase segmented-curve models with an unknown change point,with an application to the analysis of strategy shifts in a cognitive task

A program is described for fitting a regression model in which the relationship between the dependent and the independent variables is described by two regression equations, one for each of two mutually exclusive ranges of the independent variable. The point at which the change from one equation to the other occurs is often unknown, and thus must be estimated. In cognitive psychology, such models are relevant for studying the phenomenon of strategy shifts. The program uses a (weighted) least squares algorithm to estimate the regression parameters and the change point. The algorithm always finds the global minimum of the error sum of squares. The model is applied to data from a mental-rotation experiment. The program’s estimates of the point at which the strategy shift occurs are compared with estimates obtained from a nonlinear least squares minimization procedure in SPSSX.     

Specific Psychosocial Issues of Individuals Undergoing Genetic Counseling for Cancer – A Literature Review

Approximately 25 % of individuals undergoing genetic counseling for cancer experiences clinically relevant levels of distress, anxiety and/or depression. However, these general psychological outcomes that are used in many studies do not provide detailed information on the specific psychosocial problems experienced by counselees. The aim of this review was to investigate the specific psychosocial issues encountered by individuals undergoing genetic counseling for cancer, and to identify overarching themes across these issues. A literature search was performed, using four electronic databases (PubMed, PsychInfo, CINAHL and Embase). Papers published between January 2000 and January 2013 were selected using combinations, and related indexing terms of the keywords: ‘genetic counseling’, ‘psychology’ and ‘cancer’. In total, 25 articles met our inclusion criteria. We identified the specific issues addressed by these papers, and used meta-ethnography to identify the following six overarching themes: coping with cancer risk, practical issues, family issues, children-related issues, living with cancer, and emotions. A large overlap in the specific issues and themes was found between these studies, suggesting that research on specific psychosocial problems within genetic counseling has reached a point of saturation. As a next step, efforts should be made to detect and monitor these problems of counselees at an early stage within the genetic counseling process.     

Psychological functioning of recently bereaved, middle-aged women: the first 13 months

This study examined the natural course of psychological functioning in recently bereaved middle-aged women. 69 widows were assessed four times (T1-T4) between the period of 4 to 13 mo. after the loss and were compared to a matched nonwidowed group of 57. Of the SCL-90 feelings of depression, agoraphobic behavior, anxiety, hostility, somatization, feelings of insufficiency, and sleep disorders were heightened at 4 mo. after bereavement compared to the norm group. Significantly higher psychological dysfunctioning was found on all SCL-90 subscales than for non-widows. Over time, a decrease in psychological dysfunction was found for most widows; however, not every widow appeared to recover psychologically, and 17% of the widows showed severe psychological dysfunctioning at 13 mo. postbereavement (T4). With respect to the predictive value of the Total score on the SCL-90, at 13 mo., 27% of these widows had scores indicating severe psychological dysfunctioning; these were comparable to their scores at 4 mo. postbereavement.