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.     

Compliance to a cell phone-based ecological momentary assessment study: The effect of time and personality characteristics

Ecological momentary assessment (EMA) is a method that is now widely used to study behavior and mood in the settings in which they naturally occur. It maximizes ecological validity and avoids the limitations of retrospective self-reports. Compliance patterns across time have not been studied. Consistent compliance patterns could lead to data not missing at random and bias the results of subsequent analyses. In order to use modern statistical approaches for handling missing data, it is important to include variables predicting missing values into the statistical analysis. Therefore, these predictors have to be known and measured. The authors collected data on 3 four-item mood scales measuring well-being, wakefulness, and nervousness on 6 occasions per day for 7 days (N = 305) and examined compliance rate across time, within day, and within week. Results show good global compliance (mean compliance: 74.9% of calls answered). Compliance varied more within day than within week. Within day, it was lower for the first call of the day between 9 p.m. and 11 p.m. and higher for the call between 5 p.m. and 7 p.m. Within week, calls were equally answered across days of the week, but, as the study progressed, there was a slight drop in compliance with a progressive decrease that was stronger for the first 2 calls. Compliance on the person level did not depend on personality or on satisfaction with life. Practical consequences of the results for conducting ambulatory assessment studies are discussed, and some recommendations are given. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Dreaming without REM sleep

To test whether mental activities collected from non-REM sleep are influenced by REM sleep, we suppressed REM sleep using clomipramine 50mg (an antidepressant) or placebo in the evening, in a double blind cross-over design, in 11 healthy young men. Subjects were awakened every hour and asked about their mental activity. The marked (81%, range 39-98%) REM-sleep suppression induced by clomipramine did not substantially affect any aspects of dream recall (report length, complexity, bizarreness, pleasantness and self-perception of dream or thought-like mentation). Since long, complex and bizarre dreams persist even after suppressing REM sleep either partially or totally, it suggests that the generation of mental activity during sleep is independent of sleep stage.     

Perhaps There Is Accounting for Taste: Evaluating the Creativity of Products

Ratings on a creativity rating scale of students' designs of a hands-free mobile phone holder were compared for 2 sets of raters: experts (professional art teachers) and novices (visual art students). Reliabilities of total creativity scores were high for both groups, and interjudge consistency on total creativity scores, as well as on grades, was high among novices, but not as high among experts. Correlations between grades and total functional creativity scores within and across groups of raters (experts and novices) were highly significant. Scores on the scale resembled those yielded by assessments using grades and the scale did not yield better consistency among judges than conventional grades. Nonetheless, it provided a differentiated assessment of products that made it possible to explain the basis of experts' opinions and the reasons for disagreement, and to discuss the strengths and weaknesses of students' designs in a systematic and differentiated way.