Search

International audience; The present study examined the evolution of the behavioral performance, subjectively perceived difficulty, and hemodynamic activity of the prefrontal cortex as a function of cognitive load during two different cognitive tasks tapping executive functions. Additionally, it investigated therelationships between these behavioral, subjective, and neuroimaging data. Nineteen right-handed young adults (18–22 years) were scanned using continuous-wave functional near-infrared spectroscopy during the performance of n-back and random number generation tasks in three cognitiveload conditions. Four emitter and four receptor optodes were fixed bilaterally over the ventrolateral and dorsolateral prefrontal cortices to record the hemodynamic changes. A self-reported scale measured the perceived difficulty. The findings of this study showed that an increasing cognitive loaddeteriorated the behavioral performance and increased the perceived difficulty. The hemodynamic activity increased parametrically for the three cognitive loads of the random number generation task and in a two-back and three-back compared to a one-back condition. In addition, the hemodynamic activity was specifically greater in the ventrolateral prefrontal cortex than in the dorsolateral prefrontal cortex for both cognitive tasks (random number generation and n-back tasks). Finally, the results highlighted some links between cerebral oxygenation and the behavioral performance, but not the subjectively perceived difficulty. Our results suggest that cognitive load affects the executive performance and perceived difficulty and that fNIRS can be used to specify the prefrontal cortex’s implications for executive tasks involving inhibition and working memory updating.

Introduction: The digitalized PREVED (PREgnancy, PreVention, Endocrine Disruptor) questionnaire was used in the clinical practices of health professionals (HP) who adhered to the MEDPREVED strategy. The objectives were to assess the strategy and to determine if it could improve access to endocrine disruptor (ED) exposure prevention. Methods: After having filled in the digital questionnaire in HP waiting rooms, patients were invited to talk about ED exposure during the consultation. HPs were previously trained in ED and had received a prevention kit for their patients. After the seven-month implementation phase, the evaluation phase consisted of five mixed assessments: interviews with: (i) patients who were young children’s parents; (ii) patients in the general population; (iii) paediatricians; (iv) midwives; and a quantitative study on GPs. Assessment concerned feasibility, accessibility, and usefulness of the strategy; we then used the Levesque model to evaluate how it could improve access to ED exposure prevention. Results: The study included 69 participants. The strategy appeared feasible for the filling-out step due to digital and environment access. However, it depended on patient and HP profiles. The strategy seemed useful insofar as it facilitated reflexive investment, an intention to healthy behaviour and, rather rarely, talk about ED exposure. The beginning of this discussion depended on time, prioritizing of the topic and HP profile. The strategy has confirmed the Levesque model’s limiting factors and levers to access ED prevention. Conclusions: The MEDPREVED strategy is feasible, accessible, and useful in clinical prevention practice. Further study is needed to measure the impact on knowledge, risk perception and behavior of beneficiaries of the MEDPREVED strategy in the medium and long term.

It was more than 45 years ago that Gunnar Johansson invented the point-light display technique. This showed for the first time that kinematics is crucial for action recognition, and that humans are very sensitive to their conspecifics' movements. As a result, many of today's researchers use point-light displays to better understand the mechanisms behind this recognition ability. In this paper, we propose PLAViMoP, a new database of 3D point-light displays representing everyday human actions (global and fine-motor control movements), sports movements, facial expressions, interactions, and robotic movements. Access to the database is free, at https://plavimop.prd.fr/en/motions . Moreover, it incorporates a search engine to facilitate action retrieval. In this paper, we describe the construction, functioning, and assessment of the PLAViMoP database. Each sequence was analyzed according to four parameters: type of movement, movement label, sex of the actor, and age of the actor. We provide both the mean scores for each assessment of each point-light display, and the comparisons between the different categories of sequences. Our results are discussed in the light of the literature and the suitability of our stimuli for research and applications.

International audience

Episodic memory decline with aging may be due to an age-related deficit in encoding processing, older adults having increasing difficulty to self-initiate encoding strategies that support later retrieval. Using event-related potentials (ERPs), the present study explored for the first time the neural correlates of successful encoding in a resource-dependent episodic memory task, in which participants had to self-initiate processes at both encoding and retrieval. At the behavioral level, results confirm the better memory performance of young than older adults. Comparing the neural activity elicited by studied items that were and were not subsequently recalled (Subsequent Memory Effect, SME), electrophysiological data revealed that younger adults showed a significant and sustained SME, shifting from parietal to frontal areas, suggesting that they self-initiated deep encoding strategies. In older adults, the duration of brain activity was shorter and located more in the parietal than frontal areas, suggesting that they used shallow rather than deep processes. Consistent with the hypothesis of a deficit in self-initiated strategies in aging, our findings suggest that when older adults are faced with a difficult memory task (no encoding support and no cue at retrieval), they engage fewer elaborative strategies than young adults, resulting in impaired episodic memory performance.

The present study aimed to examine the effects of chronological age and cardiorespiratory fitness (CRF) on cognitive performance and prefrontal cortex activity, and to test the compensation-related utilization of neural circuits hypothesis (CRUNCH). A total of 19 young adults (18&ndash, 22 years) and 37 older ones (60&ndash, 77 years) with a high or low CRF level were recruited to perform a working memory updating task under three different cognitive load conditions. Prefrontal cortex hemodynamic responses were continuously recorded using functional near-infrared spectroscopy, and behavioral performances and perceived difficulty were measured. Results showed that chronological age had deleterious effects on both cognitive performance and prefrontal cortex activation under a higher cognitive load. In older adults, however, higher levels of CRF were related to increased bilateral prefrontal cortex activation patterns that allowed them to sustain better cognitive performances, especially under the highest cognitive load. These results are discussed in the light of the neurocognitive CRUNCH model.

The study of biological point-light displays (PLDs) has fascinated researchers for more than 40 years. However, the mechanisms underlying PLD perception remain unclear, partly due to difficulties with precisely controlling and transforming PLD sequences. Furthermore, little agreement exists regarding how transformations are performed. This article introduces a new free-access program called PLAViMoP (Point-Light Display Visualization and Modification Platform) and presents the algorithms for PLD transformations actually included in the software. PLAViMoP fulfills two objectives. First, it standardizes and makes clear many classical spatial and kinematic transformations described in the PLD literature. Furthermore, given its optimized interface, PLAViMOP makes these transformations easy and fast to achieve. Overall, PLAViMoP could directly help scientists avoid technical difficulties and make possible the use of PLDs for nonacademic applications.

The objective of this study was to examine age-related effects on behavioral performance and metabolic activity of the prefrontal cortex (PFC) in a dual-task paradigm involving fine-motor control and executive-function control. Thirty-one adults (20 ± 1.1 years) and 33 older adults (70.7 ± 5.1 years) performed, separately and then concurrently, a modified Fitts task on targets of different sizes (Index of Difficulty: ID = 3; 4; 5 bits) and the random number generation task (RNG). Movement time (MT) and count score (CS) were the dependent variables for the modified Fitts task and the RNG task, respectively. Relative changes in concentrations of oxyhemoglobin [HbO2] and deoxyhemoglobin [HHb] were recorded continuously on the left and right PFCs, with near-infrared spectroscopy (Oxymon MkIII-Artinis) with an acquisition rate of 10 Hz. Our results showed large motor dual-task cost in seniors compared to young adults. Regarding hemodynamic activity, we have observed a prominent activation of the PFC in the young adults compared to the seniors during the dual-task condition.

International audience; We studied the processes involved in synthesis writing, focusing on planning,editing and self-regulation strategies. The aims of the study were a) to analyse thetemporal distribution of cognitive strategies and self-regulation across the differentphases of writing, b) to identify different writing approaches (i.e., profiles), and c) toestablish the relationship between writing behavior and writing performance. Twenty-seven humanities students, who were 23 years of age on average, were asked toproduce a synthesis. The methodology combined videotaped observations, a think aloudprotocol, and an assessment of writing performance, and specific instruments wereconstructed to collect the data. Algorithms were also calculated to determine thetransitions between different types of writing behavior. Results showed that the nature,frequency, and duration of planning, editing, and self-regulation strategies variedaccording to the phase (prewriting or writing), and the most remarkable changesoccurred in the final period of writing. Moreover, although the college students’functioning generally reflected a novice approach, there were significant differencesbetween the three writer profiles we found, namelyprecise transcriber, active reviser,and spontaneous writer. Finally, writing performance was positively and significantlycorrelated with writing strategies such as taking notes and reading drafts.

International audience; Background:The brain-derived neurotrophic factor (BDNF) concentration is highest in the hippocampus comparedwith that in other brain structures and affects episodic memory, a cognitive function that is impaired in olderadults. According to the neurotrophic hypothesis, BDNF released during physical activity enhances brain plasticity andconsequently brain health. However, even if the physical activity level is involved in the secretion of neurotrophin, thisprotein is also under the control of a specific gene. The aim of the present study was to examine the effect of theinteraction between physical activity and BDNF Val66Met(rs6265), a genetic polymorphism, on episodic memory.Methods:Two hundred and five volunteers aged 55 and older with a Mini Mental State Examination score≥24participated in this study. Four groups of participants were established according to their physical activity level andpolymorphism BDNF profile (Active Val homozygous, Inactive Val homozygous, Active Met carriers, Inactive Met carriers).Episodic memory was evaluated based on the delayed recall of the Logical Memory test of the MEM III battery.Results:As expected, the physical activity level interacted with BDNF polymorphism to affect episodic memoryperformance (p< .05). The active Val homozygous participants significantly outperformed the active Met carriers andinactive Val homozygous participants.Conclusion:This study clearly demonstrates an interaction between physical activity andBDNF Val66Metpolymorphismthat affects episodic memory in the elderly and confirms that physical activity contributes to the neurotrophic mechanismimplicated in cognitive health. The interaction shows that only participants with Val/Val polymorphism benefited fromphysical activity

The serial analysis of gene expression (SAGE) is a powerful method to compare gene expression of mRNA populations. To provide quantitative expression levels on a genome-wide scale, the Cancer Genome Anatomy Project (CGAP) uses SAGE. Over 7 million SAGE tags, from 171 human cell types have been assembled. The growing number of laboratories involved in SAGE research necessitates the use of software that provides statistical analysis of raw data, allowing the rapid visualization and interpretation of results. We have created the first simple tool that performs statistical analysis on SAGE data, identifies the tags differentially expressed and shows the results in a scatter plot. It is freely available and accessible at http://bioserv.rpbs.jussieu.fr/websage/index.php.

International audience; α-Helical transmembrane proteins (TMPα) are composed of a series of helices embedded in the lipid bilayer. Due to technical difficulties, few 3D structures are available. Therefore, the design of structural models of TMPα is of major interest. We study the secondary structures of TMPα by analyzing the influence of secondary structures assignment methods (SSAMs). For this purpose, a published and updated benchmark databank of TMPα is used and several SSAMs (9) are evaluated. The analysis of the results points to significant differences in SSA depending on the methods used. Pairwise comparisons between SSAMs led to more than 10% of disagreement. Helical regions corresponding to transmembrane zones are often correctly characterized. The study of the sequence-structure relationship shows very limited differences with regard to the structural disagreement. Secondary structure prediction based on Bayes' rule and using only a single sequence give correct prediction rates ranging from 78 to 81%. A structural alphabet approach gives a slightly better prediction, i.e., only 2% less than the best equivalent approach, whereas the prediction rate with a very different assignment bypasses 86%. This last result highlights the importance of the correct assignment choice to evaluate the prediction assessment.

International audience; Triplex-forming oligonucleotides (TFOs) are sequence-specific DNA binders. TFOs provide a tool for controlling gene expression or, when attached to an appropriate chemical reagent, for directing DNA damage. Here, we report a set of rules for predicting the best out of five different triple-helical binding motifs (TM, UM, GA, GT, and GU, where M is 5-methyldeoxycytidine and U is deoxyuridine) by taking into consideration the sequence composition of the underlying duplex target. We tested 11 different triplex targets present in genes having an oncogenic role. The rules have predictive power and are very useful in the design of TFOs for antigene applications. Briefly, we retained motifs GU and TM, and when they do form a triplex, TFOs containing G and U are preferred over those containing T and M. In the case of the G-rich TFOs, triplex formation is principally dependent on the percentage of G and the length of the TFO. In the case of the pyrimidine motif, replacement of T with U is destabilizing; triplex formation is dependent on the percentage of T and destabilized by the presence of several contiguous M residues. An equation to choose between a GU and TM motif is given.