Biologie Aujourd''hui最新文献

The most emblematic metamorphoses in the animal kingdom remain those of the caterpillar into a butterfly and the tadpole into a frog. However, some other vertebrates also present, at one or more steps of their biological cycle, drastic changes in their morphology, physiology and behavior, allowing them to adapt to a new environment (habitat) and way of life, and thus considered as metamorphoses. This is the case within fish, for some representatives of teleosts (the largest group among vertebrates) and of cyclostomes (the most ancient group among vertebrates). Thus, a larval (or primary) metamorphosis takes place, as for amphibians, in pleuronectiformes (e.g. flatfish), elopomorphs (e.g. eels) and also in cyclostomes (e.g. lamprey). This larval metamorphosis is controlled, in all cases, by thyroid hormones. However, this regulation is remarkably opposite, stimulatory in teleosts as in amphibians, and inhibitory in the lamprey. These opposing regulations, as well as the presence of metamorphoses only in certain groups or even certain species, suggest that the recruitment of thyroid hormones for the control of metamorphoses would have occurred repeatedly and independently during the evolution of vertebrates. The neuroendocrine control of the production of thyroid hormones during larval metamorphosis is ensured in amphibians by the stimulatory control of pituitary thyrotropin, itself under the stimulatory control of hypothalamic corticotropin-releasing hormone instead of the thyrotropin-releasing hormone classically involved in the thyrotropic control of metabolism. A similar neuroendocrine control would also occur for teleost larval metamorphosis, but investigations are yet limited. Data are still lacking concerning the neuroendocrine control of the production of thyroid hormone which exerts an inhibitory control on lamprey metamorphosis. In some amphidromous migratory fishes, a so-called secondary metamorphosis, because it occurs at the juvenile stage, allows the passage from the freshwater (river) to the seawater (ocean). These are silvering in eels and smoltification in salmons. Salmon smoltification is a transition between two phases of juvenile body growth, under the positive control of thyroid hormones, as the larval metamorphosis of amphibians and teleosts. In contrast, eel silvering marks the end of the feeding and body growth phase as well as the initiation of the reproductive phase, and is controlled by the gonadotropic axis with sex steroids. The additional involvement of other hormones, such as cortisol for larval and secondary metamorphosis and growth hormone for smoltification, has also been demonstrated in the control of vertebrate metamorphoses. Overall, the larval (primary) and secondary metamorphoses observed in various vertebrates, and the recruitment of thyroid hormones and different neuroendocrine axes for their triggering, have contributed to the evolution of complex life cycles adapted to diverse habitats.

Major depressive disorder (MDD) is a prevalent and disabling condition affecting over 350 million individuals worldwide. Although conventional antidepressants targeting serotonin, dopamine, and noradrenaline pathways provide benefit for many, a substantial proportion of patients experience inadequate response. Treatment-resistant depression (TRD), defined by failure to respond to at least two antidepressant trials, affects approximately 30% of patients with MDD and poses significant clinical challenges. Emerging research is exploring novel therapeutics such as psychedelics, notably LSD (lysergic acid diethylamide). Unlike standard antidepressants that target singular pathways, LSD modulates both the serotonin system, particularly the 5-HT2A receptor, and the glutamatergic system, which are critical in neurocircuitry underlying mood regulation. This dual mechanism may enhance neuroplasticity, potentially accounting for the rapid and sustained antidepressant effects observed in preliminary studies. Ongoing clinical trials aim to evaluate the efficacy and safety of LSD-assisted therapy in MDD, especially TRD. Methodological challenges include designing appropriate placebo controls and ensuring rigorous psychological support to manage the acute psychedelic experience. While still investigational, LSD-assisted therapy represents a promising avenue that may complement existing treatments. Further research is necessary to confirm its clinical utility and establish protocols for safe integration into psychiatric practice.

For centuries, the question of human uniqueness has fueled scientific and philosophical debates. Humans have often been portrayed as singular beings endowed with abstract abilities such as tool use (Homo habilis), economic reasoning and theory of mind (Homo economicus), aesthetic sensibility (Homo aestheticus), or awareness of death and spirituality (Homo deus). However, advances in ethology and evolutionary anthropology have uncovered in non-human species behaviors once thought to be exclusively human. This paper explores three of these domains - culture, mourning, and art - through a comparative approach across human and non-human primates. By examining mechanisms of social transmission, behavioral expressions related to death, and graphic productions such as drawing, we discuss cognitive continuities between species, methodological challenges (notably anthropomorphism), and the broader implications for redefining the boundary between nature and culture. Our findings suggest that rather than representing absolute distinctions, these capacities reveal shared evolutionary roots of cognition, emotion, and creativity across the primate lineage.

Birdsong represents a model of choice for studying the biological mechanisms underlying vocal learning, a rare capacity in the animal kingdom that is shared in particular by humans. They learn their song through imitation during a sensitive period of their development, a process reminiscent of language acquisition in human infants. Neuro-anatomically, they possess specialized brain circuits dedicated to song production and learning. Furthermore, oscines demonstrate cognitive abilities including memory, attention, and behavioral flexibility, which support vocal learning. General intelligence refers to an overall cognitive capacity that allows for the solving of varied problems, while modularity posits that the human mind is composed of specialized cognitive modules, each dedicated to a particular type of information processing. In birds, vocal learning abilities may reveal insights into cognitive abilities of an individual. While several studies have obtained mixed results regarding the existence of a link between song structure and cognitive abilities at the individual level, a recent study tends to show a link between vocal learning abilities (in particular the size of the vocal repertoire including song and calls, and the ability to imitate heterospecific sounds, throughout life) and problem-solving ability, at the specific level. These studies consolidate birdsong as a relevant model to study the neurobiological, molecular and physiological substrates of vocal learning and cognitive abilities. They also highlight the interest of non-human animal models in understanding the evolution of vocal communication and associated cognitive functions.

In order to optimise their performance, athletes are looking for innovative, efficient and reliable training approaches. The development of electroencephalography and neurofeedback (NF) offers the opportunity to create innovative cognitive training procedures. Indeed, these technologies allow athletes to benefit from a feedback during mental training sessions and to objectively assess performance and progress. In addition, NF makes it possible to guide the athletes towards optimal cognitive strategies according to their objectives, and has a motivational dimension that pushes them to engage in the sessions. We first introduce the usefulness of NF to improve sports performance. Then, we review the current results concerning its efficiency. Finally, we provide an overview of the literature showing the heterogeneity of the studies published on the subject, focusing mainly on the aspects that could explain the variability of reported data.

This review article presents an in-depth characterization of the genus Penicillium, a major group of filamentous fungal species known for their biological diversity and ecological impact. Methods for the identification of the various Penicillium species combine macroscopic, microscopic and molecular approaches, as well as phylogenetic analysis. In a first part, the ecology of the Penicillium species, their distribution in various habitats and their key role in ecosystems are presented. Particular emphasis is then placed on Penicillium's ability to produce secondary metabolites with a wide variety of biological and pharmacological properties, including anti-microbial molecules, antioxidants, anti-inflammatory, anti-diabetic, anti-cancer and anti-viral compounds. Because these metabolites are of major interest in biotechnology and pharmaceutical industry, further research and development based on the yet untapped therapeutical and economical potential of this fungal genus should be promoted.

Lactate, long relegated to the status of a mere metabolic waste product, is now recognized as a central metabolite in energy metabolism, a recyclable substrate, and a cellular signaling mediator. Its production, primarily by glycolytic muscle fibers, allows for the regeneration of cytosolic NAD⁺ necessary for the continuation of glycolysis during high-intensity exercises. Its export via MCT4 lactate/proton transporters and its uptake by other tissues, especially oxidative muscle fibers via MCT1 transporters, underscore its role as a metabolic intermediate rather than a waste product. Its co-transport with protons across the sarcolemmal membrane contributes to intracellular pH regulation. Furthermore, lactate plays a role in regulating oxidative energy metabolism adaptations, by activating the mitochondrial biogenesis cofactor PGC-1α and modulating the expression of mitochondrial markers. Additionally, by binding to the G protein-coupled receptor GPR81, lactate may modulate key signaling pathways such as ERK1/2 and Akt-mTOR, which are involved in muscle hypertrophy, insulin sensitivity, and lipid regulation. In doing so, it links its metabolic functions to major adaptive processes triggered by physical exercise. However, this functional role still requires further elucidation.

Social behaviour is fundamental to survival and adaptation, relying on complex, interacting neurobiological systems in which the neuropeptide oxytocin (OT) and the neurotransmitter dopamine (DA) play pivotal roles in regulating social bonding, motivation, and reward processing. This review synthesises recent advances in understanding the bidirectional interactions between OT and DA within key nodes of the brain's reward circuitry, including the nucleus accumbens, ventral tegmental area, amygdala, and medial prefrontal cortex. We examine how these interactions support a wide range of social behaviours in humans and animals, from reproductive bonds such as pair bonding and parental care to non-reproductive interactions like social exploration, cooperation, and aggression. A central focus is the disruptive impact of psychostimulants (e.g., cocaine, amphetamines) on OT-DA balance in rodents. These substances alter DA signalling, shifting reward valuation and reducing the prioritisation of natural social rewards while increasing the drive for psychostimulant-seeking behaviour. This imbalance impairs social motivation and bonding. Importantly, positive social interactions can serve as competing natural rewards that prevent, and in some cases reverse, psychostimulant-seeking behaviours, highlighting the therapeutic potential of targeting OT-DA pathways. By integrating findings from animal models and human studies, this review proposes a framework for understanding how the brain arbitrates between social and pharmacological rewards, and how this balance is modulated by internal states, environmental factors, and the pathological effects of addictive substances.

Motor imagery (MI), the mental representation of an action without intention to physical execution, activates neural networks largely overlapping with those involved in actual motor performance. While MI has long been used as an adjunct to physical training, its potential to induce corticomotor plasticity and optimize elite performance remains insufficiently understood. Bridging fundamental neuroscience and applied sport science, we investigated how MI reshapes perception-action coupling and supports force enhancement, inter-skill transfer, and neuromuscular efficiency in high-level athletes. Our findings demonstrate that MI can induce measurable cortico-muscular connectivity changes, prime the central nervous system, and improve force production when integrated into resistance training. In field-based studies with elite CrossFit athletes, MI enhanced power performance and enabled performance gains to transfer across distinct yet biomechanically related tasks. Furthermore, we show that MI's effects are magnified when applied concomitantly with physical practice or when combined with non-invasive peripheral stimulation techniques (e.g. tendon vibration, transcutaneous vagus nerve stimulation). We propose MI as an active endogenous neuromodulation strategy, moving beyond its classical role as a cognitive training tool. By integrating MI with multimodal interventions, we aim to develop new neuromotor reprogramming paradigms prompting corticomotor remapping to facilitate elite sports performance and neurorehabilitation. Our approach positions MI at the crossroads of motor control, applied neurophysiology, and sports science to delineate original perspectives regarding how perception-action networks adapt to achieve elite performance.