Memory traces compete under regimes of limited Arc protein synthesis: Implications for memory interference

Recently encoded information can be lost in the presence of new information, a process called 'retrograde interference'. Retrograde interference has been extensively described for more than a century; however, little is known about its underlying mechanisms. Different approaches agree on the need of the synthesis of plasticity related proteins (PRPs) to consolidate a long-term memory (LTM). Our hypothesis is that when PRPs are limited, interference of a task over LTM formation of another may be due to the utilization of protein resources common to both tasks. Here, by combining the tasks of inhibitory avoidance (IA) and open field (OF) exploration in rats, we show that memory traces compete for their stabilization if PRPs are limited. As a result, LTM is formed for only one of the tasks with a consequent decrease in the memory for the other. Furthermore, infusing Arc antisense oligonucleotide into the dorsal hippocampus, we found that Arc is necessary for LTM formation of these two types of learning tasks and is one of the PRPs that can be shared between them when animals are trained in both OF and IA. In sum, these findings suggest that under conditions of reduced protein availability, a learning task interferes with LTM formation of another by using the available PRPs.     

The early development of human mirror mechanisms: evidence from electromyographic recordings at 3 and 6 months

In primates and adult humans direct understanding of others' action is provided by mirror mechanisms matching action observation and action execution (e.g. Casile, Caggiano & Ferrari, 2011). Despite the growing body of evidence detailing the existence of these mechanisms in the adult human brain, their origins and early development are largely unknown. In this study, for the first time, electromyographic (EMG) measures were used to shed light on the emergence of mirror motor mechanisms in infancy. EMG activity was recorded while 6‐ and 3‐month‐old infants watched two videos displaying an agent reaching for, grasping and bringing an object either to the mouth or to the head. Results indicate that the motor system of 6‐month‐olds, but not 3‐month‐olds, was recruited and selectively modulated during observation of the goal‐directed actions, favoring the idea that mirror mechanisms driving action understanding gradually emerge during early development.     

Differential Memory Test Sensitivity for Diagnosing Amnestic Mild Cognitive Impairment and Predicting Conversion to Alzheimer's Disease

ABSTRACT

Episodic memory is the first and most severely affected cognitive domain in Alzheimer's disease (AD), and it is also the key early marker in prodromal stages including amnestic mild cognitive impairment (MCI). The relative ability of memory tests to discriminate between MCI and normal aging has not been well characterized. We compared the classification value of widely used verbal memory tests in distinguishing healthy older adults (n = 51) from those with MCI (n = 38). Univariate logistic regression indicated that the total learning score from the California Verbal Learning Test-II (CVLT-II) ranked highest in terms of distinguishing MCI from normal aging (sensitivity = 90.2; specificity = 84.2). Inclusion of the delayed recall condition of a story memory task (i.e., WMS-III Logical Memory, Story A) enhanced the overall accuracy of classification (sensitivity = 92.2; specificity = 94.7). Combining Logical Memory recognition and CVLT-II long delay best predicted progression from MCI to AD over a 4-year period (accurate classification = 87.5%). Learning across multiple trials may provide the most sensitive index for initial diagnosis of MCI, but inclusion of additional variables may enhance overall accuracy and may represent the optimal strategy for identifying individuals most likely to progress to dementia.     

The Joint Effects of Stress,Coping, and Coping Resources on Depressive Symptoms in the Elderly

The objective of the present study was to examine the joint effects of stress, coping, and coping resources in predicting depressive symptoms. A community sample comprising 194 people aged 65 and older was interviewed. Task-oriented coping and emotion-oriented coping both appeared to be directly related to depressive symptoms. In addition, emotion-oriented coping moderated the impact of stress to varying degrees, depending on the amount of stress experienced. Coping resources (social support and coping self-efficacy) also were directly related to depressive symptoms. Furthermore, coping self-efficacy appeared to be related to the kind of coping strategies used. Respondents with higher coping self-efficacy used more task-oriented coping and less emotion-oriented coping. These findings suggest that it is advisable to include coping resources when studying stress-coping processes. Developing prevention and intervention programs aimed at teaching people adaptive coping strategies and helping them to build up their coping resources seems advisable.     

Preschoolers’ Compliance With Others’ Violations of Fairness Norms: The Roles of Intentionality and Affective Perspective Taking

ABSTRACT

Young children are remarkably compliant with social norms, especially those governing fairness and equality. Yet children also frequently observe and face opportunities to violate those social norms, particularly in situations in which doing so is self-beneficial. In 3 studies, we investigated the conditions under which children adhere to social norms using a novel resource distribution paradigm in which children met an experimenter who expressed either a norm-consistent (equal distribution) or norm-inconsistent (unequal distribution) intention. In Experiment 1, we found that preschoolers generally complied with an experimenter’s intention, regardless of its norm consistency. In Experiment 2, the experimenter again expressed a norm-consistent or norm-inconsistent intention but accidentally placed resources in the opposite distribution of that intended. Preschoolers mostly defaulted to the social norm of fairness. However, they were less likely to do so (and more likely to comply with the norm-violating experimenter) when the inequality was self-benefitting. The likelihood of norm defiance in the face of self-benefit appeared to relate to children’s affective perspective taking. In Experiment 3, we found that training preschoolers in affective perspective taking increased the likelihood children would defy a norm-violating experimenter’s unfair intention. Thus, although preschoolers were generally compliant, both fairness norms and affective perspective taking served as important mechanisms to help children selectively defy adults’ instructions and intentions.     

Being excluded by one means being excluded by all: Perceiving exclusion from inclusive others during one-person social exclusion

Although research has shown that social exclusion undermines well-being, past work has focused primarily on complete and unambiguous social exclusion in which all people in a situation exclude one individual. Might the presence of an inclusive other buffer individuals against the deleterious consequences of social exclusion? The present research investigates a novel situation, one-person exclusion, in which one person includes while another excludes. Participants played a virtual ball-tossing game in which they experienced two-person exclusion, one-person exclusion, or inclusion. Inclusive others did not buffer against the consequences of exclusion; experiencing one-person exclusion (vs. inclusion) led to perceived exclusion and lessened belongingness, similar to two-person exclusion. Moreover, instead of perceiving includers as a form of support, paradoxically, participants inaccurately believed that inclusive others had engaged in exclusion. These findings suggest that one-person exclusion is sufficient to elicit negative outcomes and that inclusive bystanders may be perceived as part of the exclusion.     

‘It's a boy because he's painting a picture’: Age differences in children's conventional and unconventional gender schemas

Two studies investigated the development of children's gender knowledge using a procedure designed to tap into children's unconventional gender beliefs. Study 1 revealed a developmental progression with 34 3‐ to 4‐year‐old children providing more unconventional reasons than conventional reasons to explain the gender of a series of drawings. By contrast, 39 5‐ to 6‐year‐old and 42 7‐ to 8‐year‐old children provided more conventional than unconventional reasons. Study 2 found that a second sample of 42 3‐ to 4‐year‐old children mastered a close‐ended assessment of gender stereotyping, while they relied on unconventional and conventional reasoning equally when explaining the gender of a series of drawings displaying conventional cues only. This research supports the model that children's conventional gender schemas do not develop before their unconventional gender schemas.     

The Experiment of Foster Care

We sought to provide a new framework for understanding the training and ongoing support of foster parents. The experiences of authorized foster parents were viewed in the context of an experiment, whereby foster parents entered an out-of-home care placement with preconceived ideas and expectations of what the provision of care would be like. We have investigated the experience of foster care from the perspective of the foster parent who tests expectations of providing care as one might conduct any experiment. Focus group discussion yielded five global domains of foster care experience: birth family, motivation, agency influences, relationship impacts, and attachment. Foster carers commonly described these domains as central to the overall experience of providing foster care. Furthermore, specific experiences within each domain were seen to either encourage or discourage the further provision of foster care. Individual interviews regarding the practical experiences related to these domains uncovered struggles of foster parents who sought to understand their role identity as a “foster parent”, and their self identity as a “mother”. We discuss implications arising from the experience of these domains of care and their related struggles.     

Age-related quantitative and qualitative changes in decision making ability

The "frontal aging hypothesis" predicts that brain senescence affects predominantly the prefrontal regions. Preliminary evidence has recently been gathered in favour of an age-related change in a typically frontal process, i.e. decision making, using the Iowa Gambling Task (IGT), but overall findings have been conflicting. Following the traditional scoring method, coupled with a qualitative analysis, in the present study we compared IGT performance of 40 young (mean age: 27.9+/-4.7) and 40 old (mean age: 65.4+/-8.6) healthy adults and of 18 patients affected by frontal lobe dementia of mild severity (mean age: 65.1+/-7.4, mean MMSE score: 24.1+/-3.9). Quantitative findings support the notion that decision making ability declines with age; moreover, it approximates the impairment observed in executive dysfunction due to neurodegeneration. Results of the qualitative analysis did not reach statistical significance for the motivational and learning decision making components considered, but approached significance for the attentional component for elderly versus young normals, suggesting a possible decrease in the ability to maintain sustained attention during complex and prolonged tasks as the putative deficit underlying impaired decision making in normal aging.