The neural cell adhesion molecule-derived peptide FGL facilitates long-term plasticity in the dentate gyrus in vivo

The neural cell adhesion molecule (NCAM) is known to play a role in developmental and structural processes but also in synaptic plasticity and memory of the adult animal. Recently, FGL, a NCAM mimetic peptide that binds to the Fibroblast Growth Factor Receptor 1 (FGFR-1), has been shown to have a beneficial impact on normal memory functioning, as well as to rescue some pathological cognitive impairments. Whether its facilitating impact may be mediated through promoting neuronal plasticity is not known. The present study was therefore designed to test whether FGL modulates the induction and maintenance of synaptic plasticity in the dentate gyrus (DG) in vivo. For this, we first assessed the effect of the FGL peptide on synaptic functions at perforant path-dentate gyrus synapses in the anesthetized rat. FGL, or its control inactive peptide, was injected locally 60 min before applying high-frequency stimulation (HFS) to the medial perforant path. The results suggest that although FGL did not alter basal synaptic transmission, it facilitated both the induction and maintenance of LTP. Interestingly, FGL also modified the heterosynaptic plasticity observed at the neighboring lateral perforant path synapses. The second series of experiments, using FGL intracerebroventricular infusion in the awake animal, confirmed its facilitating effect on LTP for up to 24 h. Our data also suggest that FGL could alter neurogenesis associated with LTP. In sum, these results show for the first time that enhancing NCAM functions by mimicking its heterophilic interaction with FGFR facilitates hippocampal synaptic plasticity in the awake, freely moving animal.     

Sex differences in expressive drawing

We examined sex differences in expressive drawings produced by 105 boys and 105 girls aged 9-15 years. The drawings were classified according to the type of expressive strategy used to depict emotion (literal, content, abstract, or any combination of these), and rated according to the complexity of that strategy. A creative/divergent thinking task (figural form) was used to assess the relationship between expressive drawing and figural creativity. As predicted, girls scored higher than boys on the expressive drawing task. Specifically, girls relied less often on literal strategies alone and were more likely to combine literal expression with metaphorical (content and abstract) expression than boys. There was a linear relationship between expressive drawing and divergent thinking scores. These results are consistent with the idea that boys and girls differ in the expressive component of emotion, and suggest that these sex differences extend to the expressive drawing domain. They also suggest that divergent thinking may be involved in the ability to draw expressively.     

The impact of physical activity and sex differences on intraindividual variability in inhibitory performance in older adults

It is well-known that processing speed and executive functions decline with advancing age. However, physical activity (PA) has a positive impact on cognitive performances in aging, specifically for inhibition. Less is known concerning intraindividual variability (iiV) in reaction times. This study aims to investigate the influence of PA and sex differences on iiV in inhibitory performance during aging. Healthy adults were divided into active and sedentary groups according to PA level. To analyse iiV in reaction times, individual mean, standard deviation and the ex-Gaussian parameters were considered. An interaction between activity level and sex was revealed, sedentary females being slower and more variable than sedentary men. No sex differences were found in the active groups. These results indicate that the negative impact of sedentariness on cognitive performance in older age is stronger for females. The present findings underline the need to consider sex differences in active aging approaches.     

About why there is a shift from cardinal to ordinal processing in the association with arithmetic between first and second grade

Digit comparison is strongly related to individual differences in children's arithmetic ability. Why this is the case, however, remains unclear to date. Therefore, we investigated the relative contribution of three possible cognitive mechanisms in first and second graders’ digit comparison performance: digit identification, digit–number word matching and digit ordering ability. Furthermore, we examined whether these components could account for the well‐established relation between digit comparison performance and arithmetic. As expected, all candidate predictors were related to digit comparison in both age groups. Moreover, in first graders, digit ordering and in second graders both digit identification and digit ordering explained unique variance in digit comparison performance. However, when entering these unique predictors of digit comparison into a mediation model with digit comparison as predictor and arithmetic as outcome, we observed that whereas in second graders digit ordering was a full mediator, in first graders this was not the case. For them, the reverse was true and digit comparison fully mediated the relation between digit ordering and arithmetic. These results suggest that between first and second grade, there is a shift in the predictive value for arithmetic from cardinal processing and procedural knowledge to ordinal processing and retrieving declarative knowledge from memory; a process which is possibly due to a change in arithmetic strategies at that age. A video abstract of this article can be viewed at: https://youtu.be/dDB0IGi2Hf8     

Neural functional organization of hallucinations in schizophrenia: Multisensory dissolution of pathological emergence in consciousness

Although complex hallucinations are extremely vivid, painful symptoms in schizophrenia, little is known about the underlying mechanisms of multisensory integration in such a phenomenon. We investigated the neural basis of these altered states of consciousness in a patient with schizophrenia, by combining state of the art neuroscientific exploratory methods like functional MRI, diffusion tensor imaging, cortical thickness analysis, electrical source reconstruction and trans-cranial magnetic stimulation. The results shed light on the functional architecture of the hallucinatory processes, in which unimodal information from different modalities is strongly functionally connected to higher-order integrative areas.     

How contextual and individual characteristics influence psychological needs satisfaction: The critical roles of political skill and political will

This two-study research package investigates the interactive effects of perceptions of organizational politics, political skill, and political will on psychological need satisfaction, which has been shown to predict a number of different important organizational outcomes. Drawing primarily on social/political influence and self-determination theories, we propose that although perceptions of organizational politics (i.e., as an important situational or contextual variable) can demonstrate need-thwarting effects for some, its effects can be need-satisfying for those individuals with high levels of political skill and political will. In Study 1, we analyze a sample of 142 individuals to demonstrate that possessing political skill attenuates the negative effects of perceptions of organizational politics on psychological need satisfaction. In Study 2, we analyze a sample of 420 individuals to demonstrate that respondents with high levels of both political skill and political will experience their highest levels of need satisfaction in highly political environments. Theoretical contributions, limitations and future research directions, and practical implications are discussed.     

What is the best model for girls and boys faced with a standardized mathematics evaluation situation: a hardworking role model or a gifted role model?

Same-gender role models are likely to improve girls' math performance. This field experiment examined whether the explanation given for a role model's success also influence children's math performance. Fifth graders were presented with a female or a male role model before a difficult math test and were informed about the cause of his/her math success (effort vs. ability vs. no explanation). The results showed that the gender of a hardworking role model did not influence math performance. In contrast, when the role model's success was not explained or explained by abilities, children performed better with the female role model than with the male role model. The hardworking role model and the female role model allowed reducing stereotype threat among girls.