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National audience; Les facteurs physiques de l’environnement subis quotidiennement par les animaux de laboratoire influencent leur comportement et leur physiologie. La lumière peut être une source de stress potentielle, notamment par certaines longueurs d’ondes et par son intensité. Des études menées sur des crustacés montrent qu’ils sont moins stressés quand ils sont éclairés par des couleurs rouge et orange à basse intensité lumineuse. L’objectif de notre étude est de déterminer les couleurs et l’intensité lumineuse les moins stressantes pour la crevette Litopenaeus vannamei. Dans une première expérience nous avons utilisé des lumières rouge, orange, jaune, verte, bleu ou violette à intensité lumineuse constante de 83 Lux pendant 15min, nous avons étudié le temps passé immobile ou en mouvement, le long des parois (thigmotactisme) ou dans la totalité du bassin, la vitesse moyenne, et le nombre de loopings, sursauts et battements d’yeux. Les couleurs rouge et orange sont celles avec lesquelles les crevettes étaient les plus mobiles, dans la totalité du bassin, avec la vitesse la plus faible, et avec lesquelles elles faisaient le moins de loopings, sursauts et battements d’yeux. Ces couleurs semblent donc être les moins stressantes parmi les couleurs testées. Ensuite, nous avons étudié l’effet de l’intensité lumineuse, 17, 64, 170 et 430 Lux, pour la couleur orange sur les mêmes paramètres que pour l’expérience précédente. Nous n’avons pas mis en évidence de différence de stress pour les intensités testées. Une dernière expérience réalisée dans un dispositif optomoteur vise à déterminer le spectre des couleurs visibles par des crevettes L. vannamei. En conclusion, il apparait que les conditions lumineuses les moins stressantes pour étudier le comportement des crevettes L. vannamei sont un éclairage orange ou rouge, peu importe l’intensité lumineuse. Cette expérience est novatrice car les préférences visuelles de Litopenaeus vannamei en termes de couleurs et d’intensités lumineuses étaient pour l’heure inconnues. Ces résultats permettront de mener des expériences sur ces animaux dans des conditions moins stressantes, et donc plus représentatives de leur comportement en milieu naturel.

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Les animaux sont-ils capables de se souvenir de leur passé et d’imaginer de futurs scenarios ? Est-ce qu’ils ont conscience de leur propre existence le long d’un continuum passé-présent-futur (conscience de soi dans un temps subjectif), ou mémorisent-ils leur existence comme une succession d’évènements plus ou moins juxtaposés ? L’existence de la mémoire épisodique chez les animaux non-humains, celle-là même qui nous permet d’effectuer ces voyages mentaux dans le temps, pose question car elle est intrinsèquement ancrée dans un temps et un espace subjectif. En l’absence de capacités de verbalisation permettant d’évaluer objectivement ces aspects phénoménologiques, la solution la plus simple serait de nier l’existence de cette mémoire si particulière chez l’animal : c’est notamment le point de vue de Tulving, premier à décrire et définir ce type de mémoire, et qui la considère comme une caractéristique de l’espèce humaine. Les animaux seraient capables d’apprendre, de modifier de manière flexible leur comportement en fonction de leurs expériences passées, mais resteraient invariablement bloqués dans le présent., Société des Neurosciences, Vol. 63 No 1 (2022): La Lettre - Automne / Hiver 2022

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International audience; According to the Source Monitoring Framework, the origin of a memory is remembered through the retrieval of specific features (e.g. perceptive, sensitive, affective signals). In two source discrimination tasks, we studied the ability of cuttlefish to remember the modality in which an item had been presented several hours ago. In Experiment 1, cuttlefish were able to retrieve the modality of presentation of a crab (visual vs olfactory) sensed before 1 h and 3 hrs delays. In Experiment 2, cuttlefish were trained to retrieve the modality of the presentation of fish, shrimp, and crabs. After training, cuttlefish performed the task with another item never encountered before (e.g. mussel). The cuttlefish successfully passed transfer tests with and without a delay of 3 hrs. This study is the first to show the ability to discriminate between two sensory modalities (i.e. see vs smell) in an animal. Taken together, these results suggest that cuttlefish can retrieve perceptual features of a previous event, namely whether they had seen or smelled an item. Can you tell whether you truly enjoyed your last holiday? According to the Source-Monitoring Framework (SMF), answering such a question requires you to revisit your personal past and retrieve specific features belonging to your memories (e.g. affective, perceptual and contextual features 1). For instance, I can remember that I went to my parents' home town (contextual features), and that we spent evenings talking or playing music (perceptual features) in a joyful atmosphere (affective feature). To remember these specific details and moments, I travelled mentally back through my personal past and engaged in episodic cognition processes, projecting myself in space and time to relive and re-experience the content of those personal memories, integrating the contextual, perceptual and affective features. Travelling mentally back into one's personal past is referred to as episodic memory, while retrieving specific features belonging to these episodic memories is a cognitive capacity involving source-memory processes. Source-memory is embedded into the episodic memory, and triggers semantic processes aiming at retrieving the origin of a memory and enabling to distinguish between two or more episodic memories. In humans, source-memory is mostly studied using item versus source-memory discrimination task. As the memory of the source relies on the recall of specific characteristics of a prior situation, participants are asked to retrieve the features of the context in which items were previously encountered. In such studies, participants have to recall the items they encountered earlier in opposition to new items (item memory), and then retrieve the context in which they were presented (e.g. whether the target items were read or mentally imagined 2 ; their spatial location 3 ; the list to which they belonged 4 ; the colour of the item 5 , etc; source-memory). Only few studies have focussed on source-memory in non-human animals. One single experiment mimicked the item versus source procedure in monkeys 6. Rhesus monkeys learnt to respond differently to two images (i.e. the first needed to be simply touched and the second one should be classified as bird, fish, flower, or human). At test, four images were presented (the two previously seen images and two distractors) and half of the monkeys needed to retrieve the image previously simply touched, and half of the monkeys needed to retrieve the image previously classified. Monkeys showed their ability to discriminate between the two sources when test was presented after a short delay, but they made source-memory mistakes when tested after a long delay, while still avoiding distractors (item memory preserved). Crystal and colleagues 7 studied rat's ability to discriminate between self-or externally-generated information. This study focused on another type of source-memory, called reality monitoring (i.e. did I learn this information myself, or did I learn it from someone else? 1). Apart from monkeys and rats, source-memory has not been

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Episodic memory, remembering past experiences based on unique what–where–when components, declines during ageing in humans, as does episodic-like* memory in non-human mammals. By contrast, semantic memory, remembering learnt knowledge without recalling unique what–where–when features, remains relatively intact with advancing age. The age-related decline in episodic memory likely stems from the deteriorating function of the hippocampus in the brain. Whether episodic memory can deteriorate with age in species that lack a hippocampus is unknown. Cuttlefish are molluscs that lack a hippocampus. We test both semantic-like and episodic-like memory in sub-adults and aged-adults nearing senescence (N = 6 per cohort). In the semantic-like memory task, cuttlefish had to learn that the location of a food resource was dependent on the time of day. Performance, measured as proportion of correct trials, was comparable across age groups. In the episodic-like memory task, cuttlefish had to solve a foraging task by retrieving what–where–when information about a past event with unique spatio-temporal features. In this task, performance was comparable across age groups; however, aged-adults reached the success criterion (8/10 correct choices in consecutive trials) significantly faster than sub-adults. Contrary to other animals, episodic-like memory is preserved in aged cuttlefish, suggesting that memory deterioration is delayed in this species.

International audience; Recently, the cognitive abilities of Sepia officinalis, in particular its memory, have been the subject of several studies. As memory is thought to be intrinsically directed toward the future, cuttlefish may possess the ability of foresight. However, some claims that animals cannot anticipate their future needs as they cannot escape their present state. To challenge this hypothesis, we conducted an experiment on 13 captive – reared juvenile and 18 wild – caught adult cuttlefish. Each cuttlefish was tested in a Y – maze, where they were fed until satiety. Afterwards they were proposed a choice between two arms: one with a shelter, but without any prey, and the other without a shelter but with a prey. They were confined inside the chosen arm overnight. The following day, after being fed until satiety, the same choice test was undertaken. If cuttlefish were bound to their current needs, they should choose the shelter on the two tests. However, if they anticipated their future needs (hunger during the following night) irrespective of their current needs (hiding), they should prefer the arm with the food the second day. All cuttlefish but two went to the shelter the first day, a choice consistent with their current state of motivation. The second day, whereas juvenile cuttlefish and control adults still chose the shelter, half of the adult cuttlefish preferred the arm with the food. Although the number of adults was too low to reach statistical significance, these results provide the first indication of an ability of adult cuttlefish to anticipate their future.

International audience; Pharmaceuticals, such as antidepressants are constantly released into the aquatic environment. Consequently, fluoxetine (FLX) and venlafaxine (VEN), the active molecules of Prozac(C) and Effexor(C), are detected up to several ng/L in freshwater and marine coastal waters. Both compounds act on the serotoninergic system, which may result in behavioural impairment, especially of juvenile animals presumed to be more susceptible to low concentrations. The objective of this study was to determine if environmental concentrations of FLX alone or combined with VEN could have any effect on innate burying behaviour in two juvenile marine invertebrates, i.e., Sepia officinalis and Carcinus maenas. Juvenile cuttlefish were exposed from hatching to 30 days post hatch to either FLX alone (i.e. 5 ng/L) or in mixture with VEN (i.e. 2.5 ng/L as well as 5 ng/L of each antidepressant). Juvenile crabs (< 2 cm carapace width) were exposed for a period of 34 days to 5 ng/L of FLX and a mixture of 5 ng/L of FLX and VEN each. Several parameters of sand digging behaviour were analysed weekly in both species. The occurrence of sand digging behaviour decreased in cuttlefish exposed to a mixture of FLX and VEN at the lowest concentration (2.5 ng/L each). At the mixture of 5 ng/L VEN and FLX each, a better body covering in juvenile crabs was observed. In both species, innate behaviour was modified under exposure to mixtures of FLX and VEN at environmentally realistic concentrations. These alterations were observed at an early developmental stage, when animals are particularly prone to predation. Hence, the modification of behavioural traits by exposure to pseudo-persistant antidepressants may decrease the survival of these two species in the long term.

National audience; Certains animaux sont latéralisés d'un point de vue comportemental et neurologique. Mais quelles sont les fonctions et les bases de ces différences gauche / droite ? Dans l'exemple de la détection des prédateurs et des proies, les seiches peuvent être latéralisées et leurs comportements répartis de part et d'autre de l'animal : on sait par exemple, que la plupart des seiches préfèrent le champ visuel gauche pour détecter les prédateurs et le champ visuel droit pour repérer les proies. Ainsi on peut penser que les animaux latéralisés voient leurs comportements repartis de manière équitable dans le cerveau pour un fonctionnement neurologique optimal ou la possibilité d'exprimer plus facilement ces comportements de manière simultanée.Qu'en est-il pour deux aspects d'une même fonction telle que le camouflage, dont la fonction est également d'échapper aux prédateurs ? Certains aspects du camouflage sont en effet latéralisés, comme par exemple les différences contraste où les seiches ont une préférence pour ce qu'elles observent dans l'oeil droit. Les autres aspects du camouflage (motif, posture, texture) le sont-ils tous également et du même côté, c.à.d. opposé à la détection de prédateur ? Ou bien les différents aspects du camouflage sont-ils répartis de part et d'autre du cerveau de manière équitable pour ?Nous avons réalisé des mesures la latéralisation chez des animaux de 6 à 9 mois dans les contextes de détection de prédateurs et de camouflage afin de déterminer les préférences gauche/droite chez les seiches pour ces comportements. On peut penser qu'un comportement aussi complexe que le camouflage peut voir ses différents aspects répartis équitablement de part et d'autre de son cerveau, et donc les préférences visuelles reparties entre l'oeil droit et l'oeil gauche, plutôt que d'être toutes du côté opposé à la détection de prédateur. Cette étude a pour objectif de nous permettre de pouvoir mieux comprendre la répartition des tâches dans le cerveau de ces animaux.

National audience; Source memory refers to the capacity to retrieve the origin of a memory. This origin is remembered through conscious retrieval of specific features of the memory (e.g., perceptual, affective, contextual, cognitive information). In a source discrimination task, we studied the ability of cuttlefish to remember the modality in which a prey item had been presented (i.e., a visual or an olfactory presentation of a crab). In the first study, animals were trained to associate the modality of presentation of a crab with a visual cue placed in the tank (i.e., when I see a crab, I should go to the left visual cue to obtain a reward, whereas when I smell a crab I should go to the right visual cue to collect the reward). On test, cuttlefish were presented with visual or olfactory stimulations of crab, but at this stage they did not have the opportunity to make a choice between the visual cues. After a delay, the visual cues were placed in the tank, giving cuttlefish the opportunity to make a choice (i.e. to go to the left or right visual cue).Our results showed that cuttlefish were able to remember the modality of the crab they had previously encountered. In the final test, the cuttlefish were tested with a novel prey they had never encountered before (i.e., shrimp). Results showed that cuttlefish were not able to remember the modality of presentation of the shrimp encountered before the delay, perhaps because they had made a specific association between the crab and the olfactory and visual presentations as opposed to a more general rule about the modality of presentation of prey items. In order to investigate this further, in a second experiment, cuttlefish were presented with three types of prey during training and passed several transfer tests with novel prey they had never encountered before. This time, all cuttlefish were able to remember the modality of presentation of the novel prey after a time delay. Taken together, these results show that cuttlefish could remember specific perceptual source information, namely whether they had seen or smelled the prey item.

Behavioural lateralization is widespread. Yet, a fundamental question remains, how can lateralization be evolutionary stable when individuals lateralized in one direction often significantly outnumber individuals lateralized in the opposite direction? A recently developed game theory model predicts that fitness consequences which occur during intraspecific interactions may be driving population-level lateralization as an evolutionary stable strategy. This model predicts that: (i) minority-type individuals exist because they are more likely to adopt unpredictable fighting behaviours during competitive interactions (e.g. fighting); and (ii) majority-type individuals exist because there is a fitness advantage in having their biases synchronized with other conspecifics during interactions that require coordination (e.g. mating). We tested these predictions by investigating biases in giant Australian cuttlefish during fighting and mating interactions. During fighting, most male cuttlefish favoured the left eye and these males showed higher contest escalation; but minority-type individuals with a right-eye bias achieved higher fighting success. During mating interactions, most male cuttlefish favoured the left eye to inspect females. Furthermore, most male cuttlefish approached the female's right side during a mating attempt and these males achieved higher mating success. Our data support the hypothesis that population-level biases are an evolutionary consequence of the fitness advantages involved in intraspecific interactions.

Behavioural lateralization is widespread. Yet, a fundamental question remains, how can lateralization be evolutionary stable when individuals lateralized in one direction often significantly outnumber individuals lateralized in the opposite direction? A recently developed game theory model predicts that fitness consequences which occur during intraspecific interactions may be driving population-level lateralization as an evolutionary stable strategy. This model predicts that: (i) minority-type individuals exist because they are more likely to adopt unpredictable fighting behaviours during competitive interactions (e.g. fighting); and (ii) majority-type individuals exist because there is a fitness advantage in having their biases synchronized with other conspecifics during interactions that require coordination (e.g. mating). We tested these predictions by investigating biases in giant Australian cuttlefish during fighting and mating interactions. During fighting, most male cuttlefish favoured the left eye and these males showed higher contest escalation; but minority-type individuals with a right-eye bias achieved higher fighting success. During mating interactions, most male cuttlefish favoured the left eye to inspect females. Furthermore, most male cuttlefish approached the female's right side during a mating attempt and these males achieved higher mating success. Our data support the hypothesis that population-level biases are an evolutionary consequence of the fitness advantages involved in intraspecific interactions.

International audience; Cet ouvrage propose une approche la plus large possible de la cognition animale, des mollusques aux primates non humains, en passant par les insectes et les oiseaux. Après une approche historique de l’éthologie cognitive, il présente de façon didactique les avancées les plus récentes sur la recherche dans ce domaine. Une attention toute particulière est apportée aux méthodes utilisées par les chercheurs pour appréhender différentes formes de cognition, de celles qui semblent les plus rudimentaires aux plus sophistiquées, des conditionnements aux apprentissages sociaux et à la manipulation des règles logiques. Il inclut des données récentes sur la numérosité, la perception du temps, de l’espace et la neuroéconomie. Des pistes de réflexions sur des liens entre cognition, statut et bien-être de l’animal sont proposées en fin d’ouvrage.

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International audience; Cuttlefish visually assess a range of background features to blend in with their surroundings. Previous research has shown that cuttlefish respond to conflicting visual cues (i.e. different visual information on their left and right sides) with mixed body patterns. This response to conflicting visual cues may be partially affected by asymmetric visual processing, since cuttlefish exhibit biases when processing visual information (i.e. visual lateralization). We used cuttlefish at different developmental stages (i.e. hatching, one-month, two-months) and tested whether they prioritise information perceived in their left or right visual field for brightness matching, which is a key aspect of crypsis. We also investigated whether the serotonergic system was driving this perceptual asymmetry, as this has been shown in some vertebrates. We found that cuttlefish exhibit perceptual asymmetries during brightness matching; both hatchlings and two-month-old cuttlefish exhibited a right eye preference, as the grey level perceived in the right visual field was predominately used for brightness matching. We also found asymmetries in the serotonergic system within the optic lobes (i.e. brain structures implication in visual processing). The expression of a serotonin receptor was significantly higher in the left optic lobe in the hatchlings. Moreover, the ratio of expression between the left and the right optic lobes was reversed between the hatchlings and the two-month old cuttlefish. Although we found asymmetries in both visual processing during brightness matching and the serotonergic neurotransmission system, the developmental trajectory of these asymmetries were not correlated. This suggests that this asymmetry of the serotonergic system was not driving the perceptual bias observed in our study. As the serotonergic system has been implicated in learning and memory in other cephalopod species, future research should focus on testing whether the asymmetrical expression of this serotonin receptor has a role in different kinds of learning and memory abilities.

International audience; Since the first study on episodic-like memory in scrub jays demonstrating that these birds can remember ‘what’, ‘where’ and ‘when’ components of a unique feeding event, other studies have used similar approaches to show that several vertebrate species also posses certain aspects of episodic-like memory. We recently showed that cuttlefish, cephalopod mollusks, keep track of what they have eaten, and where and how long ago they ate, in order to match their foraging behavior with the replenishing rates of different foods. Foraging in cuttlefish fulfills the criteria of ‘what’, ‘where’ and ‘when’ of unique events and thus provides behavioral evidence of episodic-like memory in an invertebrate. Because the hypothetical common ancestor of cephalopods and vertebrates dates back to approximately 600 million years ago, the evolution of episodic-like memory may provide a genuine case of convergent evolution. It has been suggested that the apparent evolutionary continuity of mental time travel in mammals may be linked to the continuity of hippocampal function. The presence of the hippocampal formation in birds, sharing common functions with the hippocampus of mammals, may have constrained the evolution of mental time travel abilities. A mechanistic, bottom-up approach is needed to determine the neural pre-requisites that enable the emergence of complex cognition, without being inextricably tied to evolution from common ancestors, as is the case in higher vertebrates. Exploring the neural underpinnings of an analogue of episodic-like memory in cephalopods will pinpoint the neural machinery necessary for the evolution of such complex cognitive ability.