In the brain, neurons are capable of modifying their connections with each other as a function of experience. When this synaptic plasticity occurs in the hippocampus region, it enables learning and memory. The neurosciences have described the mechanisms involved, but what enables the selection of events to be memorised has remained unknown until now.
Research by Lionel Dahan, Fares Sayegh and their colleagues, Lionel Mouledous, Catherine Macri, Juliana Pi Macedo, Camille Lejards, Claire Rampon, and Laure Verret (CRCA-CBI), has shown that dopamine neurons are at the origin of memory formation.
This study was published in Nature Communications on May 21.
Reference:
Ventral Tegmental Area dopamine projections to the hippocampus trigger long-term potentiation and contextual learning
Coline Monchanin, Erwann Drujont, Jean-Marc Devaud and Mathieu Lihoreau (CRCA-CBI) and their colleagues have published a study showing the impact of heavy metal pollution on the health of bees, which are essential to the proper functioning of ecosystems.
Reference
Monchanin C, Drujont E, Le Roux G, Lösel PD, Barron AB, Devaud JM, Elger A, Lihoreau M.
Environmental exposure to metallic pollution impairs honey bee brain development and cognition.
Nutrition is a major factor influencing host-parasite interactions. Animals can fight parasites by modifying their food choices to strengthen their immune systems and the parasites, on the other hand, can manipulate their host's foraging behavior to obtain the nutrients they need to thrive.
In this study, Eniko Csata, Alfonso Pérez-Escudero, Emmanuel Laury, Gérard Latil and Audrey Dussutour (CRCA-CBI) and their collaborators studied the role of nutrition in the host-parasite system: the Argentine ant (Linepithema humile) and the entomopathogenic fungus (Metarhizium brunneum), and revealed that the modification of food choices observed in ants infected by a fungus is not dictated by the parasite, but by a form of collective self-medication.
Champignon sur le régime optimal riche en acides aminés (en haut à gauche), fourmis non infectées choisissant un régime riche en sucre (en haut à droite), fourmis infectées choisissant le régime optimal du champignon riche en acides aminés (au centre), fourmi injectée avec des cellules de champignon inerte (en bas à droite).
Reference :
Csata E, Pérez-Escudero A, Laury E, Leitner H, Latil G, Heinze J, Simpson SJ, Cremer S, DussutourA.
Fungal infection alters collective nutritional intake of ant colonies
Over the past thirty years, the digitization of society has profoundly changed people's ways of life and communication. The information exchanged between individuals is increasingly taking the form of digital traces that are widely exploited by social networks and online commerce on the Internet, in particular through the use of rating and recommendation systems which allow users to discover new options or guide their choices.
Researchers from the Research Center on Animal Cognition, the Theoretical Physics Lab and the Toulouse School of Economics have studied how and under what conditions digital traces could allow groups of individuals to cooperate in an information search task and how reliable was the information imbedded in these traces. The researchers have analyzed and modeled the tagging behaviors of individuals and the way theyr use of digital traces thanks to a dedicated interactive web application integrating a rating system similar to that used by many e-commerce platforms.
The results published in PNAS show that groups of individuals can spontaneously and without any prior comunication between them use the fingerprints resulting from their notations to coordinate their search and collectively find the cells with the highest values in a table of hidden numbers. However, this study has also revealed that in competitive situations, the use of digital traces promotes deception because a large proportion of individuals then reduces the reliability of the information contained in the traces they leave.
Figures 1 & 2. Experimental setup consisting of a computer network used to study the impact of digital traces on collective information search behavior in human groups.
Figures 3 & 4. Interactive web application used by participants during the experiment. This application allows groups of subjects to independently explore the same table of numbers through a graphical interface and to interact indirectly with each other through the color traces that result from their actions.
Reference
Bassanetti, T., Escobedo, R., Cezera, S., Blanchet, A., Sire, C. & Theraulaz, G.
Cooperation and deception through stigmergic interactions in human groups.
Proceedings of The National Academy of Sciences USA
In many taxa, the subsocial route is considered the main pathway to permanent sociality, but the relative contribution of offspring interactions and parental care to the maintenance of cohesion and tolerance at advanced developmental stages remains poorly studied.
Spiders are relevant models for this question because they all show a transient gregarious phase before dispersal, and the transition to permanent sociality, which concerns approximately 20 of the ∼50,000 species, is assumed to rely on the subsocial route.
Using spiderlings of the solitary species Agelena labyrinthica, we manipulated the social context to demonstrate that tolerance in aggressive juveniles can be restored when exposed to siblings after moulting. We propose that moulting can reopen closed critical periods and renew the imprinting to social cues and thus lead to the reacquisition of tolerance. Our study highlights the critical role of contacts between juveniles in the expression of tolerance, which opens novel avenues for understanding social transitions.
Reference
Social recapitulation: moulting can restore social tolerance in aggressive spiderlings.
How behaviour changes with correlates of age in unicellular organisms remains an open question.
The main reason for this might be that single-cell organisms were mistakenly believed to be short-lived and immune to ageing.
It has now been demonstrated that some unicellular organisms such as bacteria, paramecia and yeast, undergo intrinsic changes over time that affect their behavior and physiology.
In this study, Audrey Dussutour, Angèle Rolland, Emilie Pasquier, Paul Malvezin, Cassandra Craig and Mathilde Dumas (CRCA-CBI) studied how the behavior of the slime mold Physarum Polycephalum, a unicellular organism, varies over the lifetime of individuals, and they showed that aging in the blob might be partially reversible.
Division of labour occurs in a broad range of organisms. Yet, how division of labour can emerge in the absence of pre-existing interindividual differences is poorly understood.
Using a simple but realistic model, we show that in a group of initially identical individuals, division of labour emerges spontaneously if returning foragers share part of their resources with other group members. In the absence of resource sharing, individuals follow an activity schedule of alternating between foraging and other tasks. If non-foraging individuals are fed by other individuals, their alternating activity schedule becomes interrupted, leading to task specialisation and the emergence of division of labour. Furthermore, nutritional differences between individuals reinforce division of labour. Such differences can be caused by increased metabolic rates during foraging or by dominance interactions during resource sharing.
Our model proposes a plausible mechanism for the self-organised emergence of division of labour in animal groups of initially identical individuals. This mechanism could also play a role for the emergence of division of labour during the major evolutionary transitions to eusociality and multicellularity.
Reference :
Kreider, J.J., Janzen, T., Bernadou, A. et al.
Resource sharing is sufficient for the emergence of division of labour.
Considering pairs of sheep, in group size 2, 3 and 4, we explore the relevancy of the following interactions: aligning (V), moving toward (simple attraction P) or a combination of both (V+P). Using our experimental date and mathematical simulation, three models of interactions were tested: all can interact with all (IN1); all groups members moving in front of you are possibly influential (IN2); only the closest neighbor in front of you is influential (IN3). In each moving phase, every individual could be a leader until the collective motion stops. We found that the best scenario is the following one: when an individual decide to move and become a leader, most often group members abide by moving in a cascade of departures, toward the group member (V) that precede in the file (IN3).
Figure extacted from the paper in Gómez-Nava, Bon et Peruani. 2022. (doi.org/10.1038/s41567-022-01769-8). (a) A snapshot of a large group summering In French Alps. (b) One image obtained from a simulation of a group of 40 sheep on the move using the most relevant model. Leader : darked greyed spot and its movement represented by an arrow. (c) Representation of interaction network in a goup of 13 animals, based on the IN3 model. The cascade of influence (arrow) : it propagates down the hierarchical network, individuals being represented by a circle.
Reference
Gómez-Nava, L., Bon, R. & Peruani, F.
Intermittent collective motion in sheep results from alternating the role of leader and follower.
Nat. Phys. (2022). https://doi.org/10.1038/s41567-022-01769-8
Acceptance and avoidance can be socially transmitted, especially in the case of mate choice.
In Drosophila melanogaster, when afemale observes a conspecific female (called demonstrator female) choosing to mate with one of two males, the former female (called observer female) can memorize and copy the latter female’s choice. Traditionally in mate-copying experiments, demonstrations provide two types of information to observer females, namely, the acceptance (positive) of one male and the rejection of the other male (negative).
To disentangle the respective roles of positive and negative information in Drosophila mate copying, we performed experiments in which demonstrations provided only one type of information at a time. We found that positive information alone is sufficient to trigger mate copying. This suggests that Drosophila females learn to prefer the successful males, implying that the underlying learning mechanisms may be shared with those of appetitive memory in non-social associative learning.
Following an observation by a female observer of a female demonstrator copulating with a green but not a pink, this observer copulates with the green male not because she rejects the pink, but because she chooses the green. Photo by David Villa ScienceImage CBI CNRS
Reference
Nöbel S., Monier M., Fargeot L., Lespagnol G., Danchin E., Isabel G.
In mice, insulin injection reduces the level of anxiety by modulating the activity of this neuronal population. On the contrary, in mice fed a “high fat diet”, serotonin neurons become resistant to insulin and the beneficial behavioural effects of this hormone disappear.
This work offers interesting prospects, in particular the repositioning of oral antidiabetics – which improve insulin sensitivity – in the treatment of anxiety-depressive episodes.
Extrait de la figure 1 de l’article de Martin, Bullich et al., 2022 (doi: 10.1038/s41380-022-01812-3). Identification de la présence du récepteur à l’insuline sur les neurones sérotoninergiques du noyau dorsal du raphé. Images de microscopie confocales représentant les neurones sérotoninergiques en rouges (cellules TPH2 positives) et l’ARNm du récepteur à l’insuline (points verts) détecté par fluorescence après hybridation in situ. Le panel de droite (à fort grossissement) signale le co-marquage (triangles blancs) illustrant la présence du récepteur à l’insuline sur les neurones sérotoninergiques.
Reference
Martin H, Bullich S, Martinat M, Chataigner M, Di Miceli M, Simon V, Clark S, Butler J, Schell M, Chopra S, Chaouloff F, Kleinridders A, Cota D, De Deurwaerdere P, Pénicaud L, Layé S, Guiard BP, Fioramonti X Insulin modulates emotional behavior through a serotonin-dependent mechanism.
Mol Psychiatry. 2022 Oct 7. doi: 10.1038/s41380-022-01812-3
Read more :
Contact :
