Thierry Pebayle

Very preterm infants can detect small variations in light levels in incubators.

This prospective observational study was designed to improve our understanding of the responses of very preterm infants to light level variations in incubators and to evaluate what determined those reactions.

The association between inhibition and pain tolerance in the elderly: Evidence from event‐related potentials

Age‐related alterations in both pain perception and inhibitory functions have been observed, but the relationship between the two in older adults remains unclear. Previous studies were mainly based on behavioural measures which do not allow assessment of underlying neural mechanisms.

Age-Related Decline in Cognitive Pain Modulation Induced by Distraction: Evidence From Event-Related Potentials

Distraction is known to reduce perceived pain but not always efficiently. Overlapping cognitive resources play a role in both pain processing and executive functions. We hypothesized that with aging, the analgesic effects of cognitive modulation induced by distraction would be reduced as a result of functional decline of frontal networks. Twenty-eight elderly and 28 young participants performed a tonic heat pain test with and without distraction (P + D vs P condition), and 2 executive tasks involving the frontal network (1-back [working memory] and go/no-go [response inhibition]), during which event-related potentials were recorded. A significant age-related difference in modulatory effect was observed during the pain-distraction test, with the older group reporting higher pain perception than the younger group during the P + D than during the P condition. Greater brain activity of early processes (P2 component) in both go/no-go and 1-back tasks correlated with less perceived pain during distraction in younger participants. For later processes, more cognitive control and attentional resources (increased N2 and P3 amplitude) needed for working memory processes were associated with greater pain perception in the older group. Inhibition processes were related to conscious distraction estimation in both groups. These findings indicate that cognitive processes subtended by resources in the frontal network, particularly working memory processes, are elicited more in elderly than in younger individuals for pain tolerance when an irrelevant task is performed simultaneously. Perspective: This study suggests that age-related declines in pain modulation are caused by functional degeneration of frontal cerebral networks, which may contribute to a higher prevalence of chronic pain. Analyzing the impact of frontal network function on pain modulation may assist in the development of more effective targeted treatment plans.

Observational study found that even small variations in light can wake up very preterm infants in a neonatal intensive care unit

This prospective observational study evaluated the behavioural responses of very preterm infants to spontaneous light variations.

On the selective activation of unmyelinated C-fibers using sinusoidal electrical stimulation: An ERP study

OBJECTIVEnTo verify the possibility of selective activation of C-fibers by a 5-Hz transcutaneous electrical stimulus.nnnMETHODSnBecause Aβ-, Aδ- and C-fibers have different conduction velocities, we verified the selective activation of A- and C-fibers on the basis of evoked potential latencies. We tested whether a 5-Hz sinusoidal electric stimulus could selectively activate C-fibers and consequently generate ultra-late N2/P2 components in the 750-1200 ms range.nnnRESULTSnWe found that a 5-Hz sine wave stimulus, whether of high or low intensity, elicited N2/P2 complexes only in the late latencies (160-390 ms), suggesting that A-fibers were concomitantly activated along with C-fibers.nnnCONCLUSIONSnThese findings are in agreement with those of previous simulation studies suggesting that activation of fibers of diameter less than 2.5 μm (i.e., C-fibers) at the 5-Hz frequency requires accompanying activity from Aβ- and Aδ-fibers.nnnSIGNIFICANCEnTranscutaneous electrical stimulation with sine wave currents of different frequencies does not seem to be a reliable method for the selective assessment of somatosensory pathways.

An autonomous, automated and mobile device to concurrently assess several cognitive functions in group-living non-human primates

HighlightsWe present a tool to concurrently assess several cognitive functions in primates.This experimental system combines automatization and mobility.This system allows testing cognitive performance in group‐living subjects.Using this device, macaques learned several cognitive tasks rapidly.Macaques showed high and stable performances thanks to this innovative tool. ABSTRACT Research methods in cognitive neuroscience using non‐human primates have undergone notable changes over the last decades. Recently, several research groups have described freely accessible devices equipped with a touchscreen interface. Two characteristics of such systems are of particular interest: some apparatuses include automated identification of subjects, while others are mobile. Here, we designed, tested and validated an experimental system that, for the first time, combine automatization and mobility. Moreover, our system allows autonomous learning and testing of cognitive performance in group‐living subjects, including follow‐up assessments. The mobile apparatus is designed to be available 24 h a day, 7 days a week, in a typical confined primate breeding and housing facility. Here we present as proof of concept, the results of two pilot studies. We report that rhesus macaques (Macaca mulatta) learned the tasks rapidly and achieved high‐level of stable performance. Approaches of this kind should be developed for future pharmacological and biomedical studies in non‐human primates.

Age-related decline in thermal adaptation capacities: An evoked potentials study

Aging is associated with changes in thermosensitivity and decreases in the functionality of the autonomic thermoregulation. The underlying mechanisms are, however, not fully understood. Elderly subjects may undergo functional changes in the integration process of the thermal sensory system, especially in their thermal adaptation capacities. To verify this hypothesis, we compared thermal evoked responses in younger and older subjects exposed to thermoneutral (27 °C) and warm (30 °C) environments. In the warm environment, the amplitudes of thermal evoked potentials (EPs) were significantly lower in older than in younger subjects, whereas in the thermoneutral environment, the EP amplitudes were similar in both groups. These findings suggest that thermal adaptation capacities are reduced in elderly individuals, due to a dysfunction of C-fibers with aging, particularly expressed by lowered adaptation capacities to temperature variations.

Un outil éthique, automatisé et totalement autonome pour étudier la cognition chez les primates

Les avancees scientifiques sont de plus en plus liees au developpement de nouvelles technologies. En neurosciences, les etudes comportementales apparaissent essentielles car elles permettent de mesurer la partie visible des processus cognitifs. Nous presentons ici un nouveau dispositif experimental entierement automatise visant a etudier les performances cognitives de primates non humains vivant en groupes sociaux. Les paradigmes experimentaux proposes aux singes sont directement derives des tests neuropsychologiques utilises chez l’Homme et presentes via une interface tactile. Le protocole experimental est base sur un principe de conditionnement operant permettant d’exclure toute deprivation hydrique et alimentaire ainsi que toute contrainte physique. Le module de test est disponible ad libitum. Il integre un systeme automatique de reconnaissance des sujets permettant aux singes de venir travailler de maniere totalement volontaire. Une particularite du programme que nous avons developpe est l’implementation d’un nouveau processus d’apprentissage totalement informatise et autonome, ne necessitant aucune intervention de l’experimentateur tout au long de l’etude. Base sur des algorithmes intelligents, ce dernier permet une variation en temps reel de la difficulte des tâches en fonction de l’evolution des performances individuelles. C’est ce point en particulier que l’etude visait a valider, ainsi que la capacite des singes a apprendre de maniere totalement autonome et a performer sur differentes tâches cognitives proposees en parallele sur un module de test en libre acces. Les tâches mises en place dans cette etude ciblent l’attention et le controle inhibiteur (5-Choice Serial Reaction Time), la memoire visuelle a court terme (Delayed Matching to Sample) et la memoire de travail (Self Order Spatial Search). L’etude a ete realisee sur un groupe social mixte de quatre macaques rhesus (Macaca mulatta). Dans un premier temps, cette etude a permis de valider les statuts fonctionnel et operationnel du module ainsi que du nouveau programme. Les resultats ont permis de demontrer l’efficacite du dispositif experimental pour etudier l’evolution des performances a long terme dans le cadre d’etudes integrant plusieurs tâches cognitives distinctes realisees en parallele. On note un niveau de performance au moins aussi eleve que dans la litterature, dans le cadre d’etudes adoptant une approche plus classique sur des singes isoles. Il apparait que les taux de reussite sont largement sensibles a la variation des parametres de difficultes pour l’ensemble des tâches. Ces derniers resultats sont coherents avec les donnees obtenues chez l’Homme et chez d’autres modeles animaux (rats, souris, poissons). Enfin, les sujets affichent des performances stables meme apres plusieurs mois de test. Dans un second temps, l’apprentissage autonome des tâches chez un sujet totalement naif a ete valide. Ce dernier a presente des temps d’apprentissage particulierement courts, permettant de souligner l’importance majeure d’optimiser les phases d’entrainement pour maximiser la qualite des donnees recoltees dans ce type d’approche. Nous pensons que ces resultats illustrent l’interet majeur que presente la mise en place d’un tel outil dans l’etude des processus sous-jacents aux differentes fonctions cognitives et aux multiples interactions presentes entre ces fonctions. Il resulte une augmentation de la quantite de donnees ainsi que de leur qualite, avec notamment l’affranchissement du facteur humain. De plus, cette demarche methodologique est particulierement en phase avec les nouveaux standards de l’experimentation animale. En conclusion, l’utilisation de telles approches visant a automatiser les processus de test pourrait, a notre sens, permettre de nouvelles avancees dans les domaines de la cognition et des etudes translationnelles. De plus, la generalisation de ce type de design experimentaux, a la fois ethiques et performants, devrait mettre en avant l’interet majeur du modele non humain dans ce type de recherches.Je souhaite remercier l’ensemble de l’equipe enseignante de la licence «u2009Concepteur Developpeur en Environnement Distribueu2009» de l’IUT Robert Schuman pour leur soutien dans le developpement du programmeu2009; le personnel technique du Centre de Primatologie de l’Universite de Strasbourg et son directeur, Yves Larmet, pour leur implication au quotidienu2009; la plateforme «u2009Silabe ADUEISu2009» pour la mise a disposition des locaux, des singes, ainsi que pour le financement du projet.

Appropriate Encoding Strategies Compensate for Driving Abilities in Elderly Individuals: A Virtual Reality Study

the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. Author Contributions: All authors contributed to this paper. All coauthors have full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Sponsor’s Role: None.