Application of Doehlert design combined with chemometrics tools: Example of the optimization of the elution of neurotransmitters and metabolites by HPLC.

Experimental designs are essential mathematical tools in fields like agronomy, chemistry, and analytical chemistry for optimizing processes and minimizing variations. Doehlert designs, in particular, are valued for their efficiency in exploring experimental space with minimal experiments, providing detailed insights into complex processes. In analytical chemistry, these designs are extensively used for tasks such as extraction, purification, and method optimization, allowing systematic variation of factors to enhance accuracy and efficiency.

Long-term social memory of mate copying in Drosophila melanogaster is localized in mushroom bodies.

Long-term social memory (LTSM) is a key feature to elicit the cultural inheritance of behaviour independently of genetics. However, the neurobiological basis of LTSM remains largely unknown. We previously used the Drosophila animal model, which is known to perform mate copying through observational learning of the mate choice of conspecifics to show that the expression of the rutabaga gene, a calcium/calmodulin-dependent adenylyl cyclase (AC-Rut+) that acts as a coincidence detector enabling associative learning, is necessary and sufficient in the γ-Kenyon cells (KCs) of the mushroom bodies (MBs).

Age-associated alteration of innate defensive response to a looming stimulus and brain functional connectivity pattern in mice.

Innate defensive behaviors are essential for species survival. While these behaviors start to develop early in an individual's life, there is still much to be understood about how they evolve with advancing age. Considering that aging is often accompanied by various cognitive and physical declines, we tested the hypothesis that innate fear behaviors and underlying cerebral mechanisms are modified by aging.

From Classical to Alternative Pathways of 2-Arachidonoylglycerol Synthesis: AlterAGs at the Crossroad of Endocannabinoid and Lysophospholipid Signaling.

2-arachidonoylglycerol (2-AG) is the most abundant endocannabinoid (EC), acting as a full agonist at both CB1 and CB2 cannabinoid receptors. It is synthesized on demand in postsynaptic membranes through the sequential action of phosphoinositide-specific phospholipase Cβ1 (PLCβ1) and diacylglycerol lipase α (DAGLα), contributing to retrograde signaling upon interaction with presynaptic CB1. However, 2-AG production might also involve various combinations of PLC and DAGL isoforms, as well as additional intracellular pathways implying other enzymes and substrates.

A social learning primacy trend in mate-copying: an experiment in .

Social learning is learning from the observation of how others interact with the environment. However, in nature, individuals often need to process serial social information and may favour either the most recent information (recency bias), constantly updating knowledge to match the environment, or the information that appeared first in the series (primacy bias), which may slow down adjustment to environmental change. Mate-copying is a widespread form of social learning in a mate choice context related to conformity in mate choice, and where a naive individual develops a preference for a given mate (or mate phenotype) seen being chosen by conspecifics.

Male attractiveness is subjective to exposure to males of different attractiveness in fruit flies.

Mate choice is a crucial decision in any animal. In terms of fitness, the best mate is the one that leads to the most abundant and productive offspring. Pairing with a low-quality mate would reduce fitness, generating selection for accurate and subtle mate choice in all animal species.

Ventral tegmental area dopamine projections to the hippocampus trigger long-term potentiation and contextual learning.

In most models of neuronal plasticity and memory, dopamine is thought to promote the long-term maintenance of Long-Term Potentiation (LTP) underlying memory processes, but not the initiation of plasticity or new information storage. Here, we used optogenetic manipulation of midbrain dopamine neurons in male DAT::Cre mice, and discovered that stimulating the Schaffer collaterals - the glutamatergic axons connecting CA3 and CA1 regions - of the dorsal hippocampus concomitantly with midbrain dopamine terminals within a 200 millisecond time-window triggers LTP at glutamatergic synapses. Moreover, we showed that the stimulation of this dopaminergic pathway facilitates contextual learning in awake behaving mice, while its inhibition hinders it.

No major effect of dopamine receptor 1/5 antagonist SCH-23390 on epileptic activity in the Tg2576 mouse model of amyloidosis.

The excitation-inhibition imbalance manifesting as epileptic activities in Alzheimer's disease is gaining more and more attention, and several potentially involved cellular and molecular pathways are currently under investigation. Based on in vitro studies, dopamine D1-type receptors in the anterior cingulate cortex and the hippocampus have been proposed to participate in this peculiar co-morbidity in mouse models of amyloidosis. Here, we tested the implication of dopaminergic transmission in vivo in the Tg2576 mouse model of Alzheimer's disease by monitoring epileptic activities via intracranial EEG before and after treatment with dopamine antagonists.

Fungal infection alters collective nutritional intake of ant colonies.

In animals, parasitic infections impose significant fitness costs. Infected animals can alter their feeding behavior to resist infection, but parasites can manipulate animal foraging behavior to their own benefits. How nutrition influences host-parasite interactions is not well understood, as studies have mainly focused on the host and less on the parasite.

The High-Precision Liquid Chromatography with Electrochemical Detection (HPLC-ECD) for Monoamines Neurotransmitters and Their Metabolites: A Review.

This review highlights the advantages of high-precision liquid chromatography with an electrochemical detector (HPLC-ECD) in detecting and quantifying biological samples obtained through intracerebral microdialysis, specifically the serotonergic and dopaminergic systems: Serotonin (5-HT), 5-hydroxyindolacetic acid (5-HIAA), 3,4-dihydroxyphenylacetic acid (DOPAC), dopamine (DA), 3-metoxytryptamin (3-MT) and homovanillic acid (HVA). Recognized for its speed and selectivity, HPLC enables direct analysis of intracerebral microdialysis samples without complex derivatization. Various chromatographic methods, including reverse phase (RP), are explored for neurotransmitters (NTs) and metabolites separation.

Mitochondrial OPA1 Deficiency Is Associated to Reversible Defects in Spatial Memory Related to Adult Neurogenesis in Mice.

Mitochondria are integrative hubs central to cellular adaptive pathways. Such pathways are critical in highly differentiated postmitotic neurons, the plasticity of which sustains brain function. Consequently, defects in mitochondria and in their dynamics appear instrumental in neurodegenerative diseases and may also participate in cognitive impairments.

Genetic background modulates phenotypic expressivity in OPA1 mutated mice, relevance to DOA pathogenesis.

Dominant optic atrophy (DOA) is mainly caused by OPA1 mutations and is characterized by the degeneration of retinal ganglion cells (RGCs), whose axons form the optic nerve. The penetrance of DOA is incomplete and the disease is marked by highly variable expressivity, ranging from asymptomatic patients to some who are totally blind or who suffer from multisystemic effects. No clear genotype-phenotype correlation has been established to date.

Mate copying requires the coincidence detector Rutabaga in the mushroom bodies of .

Mate choice constitutes a major fitness-affecting decision often involving social learning leading to copying the preference of other individuals (i.e., mate copying).

Enriched environmental exposure reduces the onset of action of the serotonin norepinephrin reuptake inhibitor venlafaxine through its effect on parvalbumin interneurons plasticity in mice.

Mood disorders are associated with hypothalamic-pituitary-adrenal axis overactivity resulting from a decreased inhibitory feedback exerted by the hippocampus on this brain structure. Growing evidence suggests that antidepressants would regulate hippocampal excitatory/inhibitory balance to restore an effective inhibition on this stress axis. While these pharmacological compounds produce beneficial clinical effects, they also have limitations including their long delay of action.

Fighting Flies: Quantifying and Analyzing Aggression.

Aggression is an innate behavior that likely evolved in the framework of defending or obtaining resources. This complex social behavior is influenced by genetic, environmental, and internal factors. remains an effective and exciting model organism with which to unravel the mechanistic basis of aggression due to its small but sophisticated brain, an impressive array of neurogenetic tools, and robust stereotypical behavioral patterns.

Comparing Methods for Quantifying and Analyzing Aggression.

Here, we highlight three different assays that are used to study aggression. The advantages and disadvantages of each assay are discussed, as examining different aspects of aggressive behavior presents distinct challenges to researchers. This is because aggression is not a singular behavioral unit.

Modeling bee movement shows how a perceptual masking effect can influence flower discovery.

Understanding how pollinators move across space is key to understanding plant mating patterns. Bees are typically assumed to search for flowers randomly or using simple movement rules, so that the probability of discovering a flower should primarily depend on its distance to the nest. However, experimental work shows this is not always the case.

Non-lethal fungal infection could reduce aggression towards strangers in ants.

Many parasites interfere with the behaviour of their hosts. In social animals, such as ants, parasitic interference can cause changes on the level of the individual and also on the level of the society. The ant-parasitic fungus Rickia wasmannii influences the behaviour of Myrmica ants by expanding the host's nestmate recognition template, thereby increasing the chance of the colony accepting infected non-nestmates.

Neuronal hyperexcitability in the Tg2576 mouse model of Alzheimer's disease - the influence of sleep and noradrenergic transmission.

The link between Alzheimer's disease (AD) and network hypersynchrony - manifesting as epileptic activities - received considerable attention in the past decade. However, several questions remain unanswered as to its mechanistic underpinnings. Therefore, our objectives were (1) to better characterise epileptic events in the Tg2576 mouse model throughout the sleep-wake cycle and disease progression via electrophysiological recordings and (2) to explore the involvement of noradrenergic transmission in this pathological hypersynchrony.

Individual consistency in the learning abilities of honey bees: cognitive specialization within sensory and reinforcement modalities.

The question of whether individuals perform consistently across a variety of cognitive tasks is relevant for studies of comparative cognition. The honey bee (Apis mellifera) is an appropriate model to study cognitive consistency as its learning can be studied in multiple elemental and non-elemental learning tasks. We took advantage of this possibility and studied if the ability of honey bees to learn a simple discrimination correlates with their ability to solve two tasks of higher complexity, reversal learning and negative patterning.

Human PSEN1 Mutant Glia Improve Spatial Learning and Memory in Aged Mice.

The ΔE9 mutation causes a familial form of Alzheimer's disease (AD) by shifting the processing of amyloid precursor protein (APP) towards the generation of highly amyloidogenic Aβ42 peptide. We have previously shown that the ΔE9 mutation in human-induced pluripotent stem cell (iPSC)-derived astrocytes increases Aβ42 production and impairs cellular responses. Here, we injected ΔE9 mutant astrosphere-derived glial progenitors into newborn mice and investigated mouse behavior at the ages of 8, 12, and 16 months.

2-D sex images elicit mate copying in fruit flies.

Although the environment is three-dimensional (3-D), humans are able to extract subtle information from two-dimensional (2-D) images, particularly in the domain of sex. However, whether animals with simpler nervous systems are capable of such information extraction remains to be demonstrated, as this ability would suggest a functional generalisation capacity. Here, we performed mate-copying experiments in Drosophila melanogaster using 2-D artificial stimuli.

Resource sharing is sufficient for the emergence of division of labour.

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.