Differences in neuronal activity explain differences in memory forming abilities of different populations of Lymnaea stagnalis

The ability to learn and form long-term memory (LTM) can enhance an animal's fitness, for example, by allowing them to remember predators, food sources or conspecific interactions. Here we use the pond snail, Lymnaea stagnalis, to assess whether variability between natural populations (i.e., strains) in memory forming capabilities correlates with electrophysiological properties at the level of a single neuron, RPeD1. RPeD1 is a necessary site of LTM formation of aerial respiratory behaviour following operant conditioning. We used strains from two small, separate permanent ponds (TC1 and TC2). A comparison of the two populations showed that the TC1 strain had enhanced memory forming capabilities. Further, the behavioural phenotype of enhanced memory strain was explained, in part, by differences in the electrophysiology of RPeD1. Compared to RPeD1 from the naive TC2 strain, RPeD1 from the TC1 strain has both a decreased resistance and decreased excitability. Moreover, 24h after a single 0.5h training session, those membrane properties, as well as the firing and bursting rate, decrease further in the TC1 strain but not in the TC2 strain. The initial differences in RPeD1 properties in the TC1 strain coupled with their ability to further change these properties with a single training session suggests that RPeD1 neurons from the TC1 strain are "primed" to rapidly form memory.     

Assuming too much from 'familiar' brain potentials

Familiarity is sometimes associated with midfrontal old/new (FN400) signals, but investigators assume too much by inferring familiarity whenever they identify these signals. We describe how Rosburg and colleagues (2011) made this assumption, yielding potentially faulty conclusions about the recognition heuristic. We provide an alternative interpretation emphasizing implicit processing that can underlie decision-making.     

Alternate behavioural measurements following a single operant training regime demonstrate differences in memory retention

Frequently studies of learning and memory measure a single focal behaviour; however it is likely that any learning paradigm will alter multiple behavioural traits in the same animal. We used video footage of the great pond snail (Lymnaea stagnalis), collected immediately prior to both training and testing for memory in response to operant conditioning to reduce aerial respiration, to measure two additional alternate behavioural traits: reducing the size of the pneumostome (breathing orifice) opening and shell tilt to cover the pneumostome. Typically, the training regime used here results in memory to reduce the number of breathing attempts lasting 24?h but not 72?h. However, memory duration when measured using the two additional behavioural traits differed significantly; shell tilt was short-lived lasting less than 1?h following training, whereas the reduction in pneumostome size was still apparent 72?h following training. Therefore, conclusions about the ability of L. stagnalis to retain memory in response to a single type of training regime will differ significantly depending on the focal behavioural trait measured. A significant correlation between the reduction in opening attempts and visible pneumostome area indicated that these behavioural traits are co-specialised, whereas pneumostome opening and shell tilt behaviour varied independently.     

Investigating the acute effect of an aerobic dance exercise program on neuro-cognitive function in the elderly

ObjectiveThe present study investigated the types of aerobic dance programs that positively impact cognition, such as executive function, in elderly people.DesignRandomized controlled trial.MethodThe study compared the effects of acute aerobic dance exercise on cognitive performance using two 40-min aerobic dance programs. Thirty-four elderly participants, aged 65–75 years, were randomly assigned into either free (N = 17) or combination (N = 17) style workout groups. The free style (FR) workout consisted of several patterns of movement, while the combination style (CB) workout consisted of similar patterns of movement to FR, but the patterns were joined to form a long choreographic routine. Both dance programs were controlled to be the same in exercise intensity, approximately 40% heart rate reserve. Reaction time and correct rates were measured using a task-switching reaction time test to evaluate executive cognitive performance immediately before and after the 40-min dance exercise.ResultsA two-way (dance program × pre-post dance exercise) repeated-measures analysis of variance for switch reaction time increase (switch cost) demonstrated a significant interaction (p = .006), showing that the switch cost in the CB group became smaller after the dance exercise than before (p = .009).ConclusionThe results suggest that the executive cognitive network was facilitated in a CB dance workout that has a dual-task nature and induces movement (task) interference with unexpected movement changes.     

Accuracy in parameter estimation for ANCOVA and ANOVA contrasts: sample size planning via narrow confidence intervals

Contrasts of means are often of interest because they describe the effect size among multiple treatments. High-quality inference of population effect sizes can be achieved through narrow confidence intervals (CIs). Given the close relation between CI width and sample size, we propose two methods to plan the sample size for an ANCOVA or ANOVA study, so that a sufficiently narrow CI for the population (standardized or unstandardized) contrast of interest will be obtained. The standard method plans the sample size so that the expected CI width is sufficiently small. Since CI width is a random variable, the expected width being sufficiently small does not guarantee that the width obtained in a particular study will be sufficiently small. An extended procedure ensures with some specified, high degree of assurance (e.g., 90% of the time) that the CI observed in a particular study will be sufficiently narrow. We also discuss the rationale and usefulness of two different ways to standardize an ANCOVA contrast, and compare three types of standardized contrast in the ANCOVA/ANOVA context. All of the methods we propose have been implemented in the freely available MBESS package in R so that they can be easily applied by researchers.     

Modulation of N400 in chronic non-fluent aphasia using low frequency Repetitive Transcranial Magnetic Stimulation (rTMS)

Low frequency Repetitive Transcranial Magnetic Stimulation (rTMS) has previously been applied to language homologues in non-fluent populations of persons with aphasia yielding significant improvements in behavioral language function up to 43 months post stimulation. The present study aimed to investigate the electrophysiological correlates associated with the application of rTMS through measurement of the semantic based N400 Event-related brain potentials (ERP) component. Low frequency (1 Hz) rTMS was applied to the anterior portion of the homologue to Broca’s area (pars triangularis), for 20 min per day for 10 days, using a stereotactic neuronavigational system. Twelve non-fluent persons with aphasia, 2-6 years post stroke were stimulated. Six participants were randomly assigned to receive real stimulation and six participants were randomly assigned to receive a blind sham control condition. ERP measures were recorded at baseline, 1 week and 2 months subsequent to stimulation. The findings demonstrate treatment related changes observed in the stimulation group when compared to the placebo control group at 2 months post stimulation indicating neuromodulation of N400 as a result of rTMS. No treatment related changes were identified in the stimulation group, when compared to the sham group from baseline to 1 week post stimulation. The electrophysiological results represent the capacity of rTMS to modulate neural language networks and measures of lexical-semantic function in participants with non-fluent aphasia and suggest that time may be an important factor in brain reorganization subsequent to rTMS.     

Clinical Reflection and Ritual as Forms of Participation and Interaction: Reply to Bass and Stern

We agree with the commentaries that Relational psychoanalysis has stood firmly against dichotomizing clinical reflection, on one hand, and interactional processes, on the other. Still, we wonder whether the relational literature has skewed toward interaction at the expense of concentrated attention to patients’ internal worlds. Predispositions toward interaction may diminish reflective space and quiet inwardness, which are themselves forms of analytic relating. We raise the possibility that the Relational model’s inclusive breadth, valuable as it is, might sometimes impede and even devalue discussions of specific technical matters. We consider clinical conceptualizations of ritual, “relating,” and “being in contact.”     

In Their Footsteps or Shadow? Gender Differences in Choosing a STEM Major as a Function of Sibling Configuration and Older Sibling’s Gender and Math Ability

Although the association between siblings’ compositional characteristics and educational performance has been extensively studied, the question of whether the features of a sibling group are related to substantive gendered educational preferences has not been examined. Our analysis of the National Longitudinal Survey of Youth 1979 cohort (NLSY-79) Mothers and Children Files (N?=?1545; 57% young women; 22% STEM major) showed that siblings’ compositional characteristics matter for STEM major preferences in college, but only for young women. Our findings indicated that women were more likely to prefer a STEM major if they were raised in smaller sibling groups, in male sibling group dominance, and if they had an older sister with high math achievement. These results are in line with the resource dilution approach; they shed light on the effects of being in a normative male-role sibling group climate; and they suggest that gendered outcomes are shaped by the interplay of role modeling and same-gender competitive stimulation. We also found that for young men, their preference for majoring in a STEM field was mostly driven by their own math ability. These findings suggest that socialization experiences that operate on the sibling level play a crucial role in whether girls become interested in and pursue “gender-atypical” educational choices. Our findings also underscore the need to differentiate these theoretical approaches by gender, particularly when applied to gendered outcomes such as STEM career trajectories.

     

The stigmatized perceiver: Exploring the implications of social stigma for cross-race face processing and memory

The human face is an important source of information, such as race or ethnicity, which can guide social interaction and outcomes. Research suggests that compared to majority and dominant group members, minority and subordinate group members tend to experience chronic stigma, resulting in more negative life outcomes (e.g., educational and occupational attainment). We argue that theory and research exploring face perception has not led to models that incorporate how the chronic experience of stigma may impact judgments, reflecting a gap with potential consequences for the validity and generalizability of the theories developed. We propose a framework for understanding how experiencing a socially stigmatized racial identity may lead perceivers to engage in face processing differently from their non-stigmatized counterparts. With a focus on the literature examining the cross-race effect, we explore the potential impact of chronic social stigma on three theorized moderators guiding processing and memory for same-versus cross-race faces. Our analysis suggests that future research focusing on stigmatized perceivers could help to explain some variation in findings, lead to novel theoretical development, and ultimately produce more generalizable research across several domains of inquiry.     

Religious Bias Among Religiously Conscious Black Christians in the United States

Research with White participants has demonstrated religious intergroup bias; however, religious identity may be different for Black Americans. Only religiously conscious Black Christians demonstrated a preference for Christian targets over Muslim and Atheist targets. Future research should consider what factors result in a person becoming conscious of other's religion.