Matthieu Keller

Matthieu Keller
French National Centre for Scientific Research | CNRS

PhD

About

213
Publications
39,156
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3,340
Citations
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October 2006 - present

Publications

Publications (213)
Conference Paper
BACKGROUND-AIM In seasonal anestrous goats, the introduction of a buck stimulates LH secretion and triggers ovulation, a phenomenon called “the male effect”. The sexual and endocrine responses of females to the male effect varies with the sexual behavior displayed by bucks. Bucks rendered sexually active during the sexual rest by previous exposure...
Conference Paper
Full-text available
BACKGROUND-AIM The ram effect, which is the most well-studied socio-sexual factor for inducing ovulation in sheep during the seasonal anestrus, involves the reintroduction of males to a flock of ewes in anestrus that had been isolated from rams. The introduction of the rams induces an increase in the tonic secretion of LH of the females, and a prop...
Article
Male goats rendered sexually active by exposure to a photoperiodic treatment are more efficient than untreated goats in stimulating LH secretion and ovulation in seasonally anestrous goats. This phenomenon is called the "male effect". Here, we determined whether sexually active bucks are able to stimulate the endocrine and sexual activities of othe...
Conference Paper
La estacionalidad de la reproducción es una característica de la mayoría de las razas caprinas y ovinas de latitudes subtropicales. Las hembras presentan anovulación y disminución de las concentraciones plasmáticas de LH en primavera y verano, mientras que los machos disminuyen drásticamente los niveles plasmáticos de testosterona, la producción es...
Article
Mammals living at temperate latitudes typically display annual cyclicity in their reproductive activity: births are synchronized when environmental conditions are most favorable. In a majority of these species, daylength is the main proximate factor used to anticipate seasonal changes and to adapt physiology. The brain integrates this photoperiodic...
Article
In some mammals that breed cooperatively, nonbreeding female helpers nurse offspring born to the breeding female in their group, a process known as allonursing. Previous laboratory studies have suggested that primiparous and multiparous females (those that have successfully given birth once or more, respectively) are more likely to contribute to al...
Article
Full-text available
The phytoestrogen genistein (GEN) may interfere with permanent morphological changes in the brain circuits sensitive to estrogen. Due to the frequent use of soy milk in the neonatal diet, we aimed to study the effects of early GEN exposure on some physiological and reproductive parameters. Mice of both sexes from PND1 to PND8 were treated with GEN...
Article
Seasonally breeding mammals display timely physiological switches between reproductive activity and sexual rest, which ensure synchronisation of births at the most favourable time of the year. These switches correlate with seasonal changes along the hypothalamo-pituitary-gonadal axis, but they are primarily orchestrated at the hypothalamic level th...
Article
Anticoagulant rodenticides (AR) resistance has been defined as “a major loss of efficacy due to the presence of a strain of rodent with a heritable and commensurately reduced sensitivity to the anticoagulant”. The mechanism that supports this resistance has been identified as based on mutations in the Vkorc1 gene leading to severe resistance in rat...
Article
Objective17α-Ethinylestradiol (EE2) is a synthetic compound used as an oral contraceptive in birth control pills. EE2 is a major contaminant in aquatic environments. It is considered an endocrine-disrupting chemical due to its oestrogenic activity. This study investigates the effect of repeated exposure to EE2 at a dose of 1 µg/kg·(body weight)/day...
Article
Full-text available
In mice, social behaviors are largely controlled by the olfactory system. Pheromone detection induces naïve virgin females to retrieve isolated pups to the nest and to be sexually receptive to males, but social experience increases the performance of both types of innate behaviors. Whether animals are intrinsically sensitive to the smell of conspec...
Article
Full-text available
The neuropeptide oxytocin (OT) promotes maternal care and social affiliation in adults but its importance in infant attachment still remains unknown. True animal models of infant attachment are extremely rare, and the sheep (in complement to non-human primates) is one of the few that provides the opportunity to investigate its neuroendocrinological...
Article
The ovine model could be an effective translational model but remains underexplored. Here, Blood Oxygen Level dependent functional MRI during visual stimulation and resting-state perfusion MRI were explored. We aimed at investigating the impact of isoflurane anesthesia during visual stimulation and evaluate resting cerebral blood flow and cerebral...
Article
Full-text available
Reproduction induces changes within the brain to prepare for gestation and motherhood. However, the dynamic of these central changes and their relationships with the development of maternal behavior remain poorly understood. Here, we describe a longitudinal morphometric neuroimaging study in female mice between pre-gestation and weaning, using new...
Article
Full-text available
In confined management systems, well-nourished bucks rendered sexually active by exposure to long days are efficient in fertilizing out-of-season goats. However, underfeeding is common in semi-extensive management systems and may reduce the reproductive efficiency of bucks. The objective of the present study was to determine whether nutritional sup...
Article
Full-text available
Numerous chemicals derived from human activity are now disseminated in the environment where their exert estrogenic endocrine disrupting effects, and therefore represent major health concerns. The present study explored whether Methoxychlor (MXC), an insecticide with xenoestrogens activities, given during the perinatal period (from gestational day...
Article
Full-text available
In semiarid conditions, feed is often scarce and variable with underfeeding being common; these factors can potentially induce fertility reductions in both sexes. Sexually active bucks are able to very efficiently fertilize out-of-season goats, but we do not know whether underfeeding would reduce the ability of bucks to fertilize goats during these...
Article
Full-text available
The continuous presence of active male small ruminants prevents seasonal anestrus in females, but evidence of the same mechanism operating from the females to the males is scarce. This study assessed the effects of the continuous presence of ewes in estrus in spring on ram sexual activity, testicular size and echogenicity, and LH and testosterone c...
Article
In goats and sheep from temperate and subtropical latitudes, the breeding season lasts from early autumn to late winter, whereas the anestrous season lasts from late winter to late summer. In prepubertal or post-partum females, the durations of the quiescent periods depend mainly on the season of parturitions and of nursing duration. In both situat...
Article
Full-text available
The effect of the introduction of sexually active rams in spring on LH secretion in ewes after progestagen treatment has been studied. Two rams were induced into a sexually active state by exposure to 2 months of long days (16 h of light/d) from 1 January (SAR), and another 2 rams were exposed to the natural photoperiod, so that they were not sexua...
Article
Full-text available
The water vole Arvicola terrestris is endemic to Europe where its outbreak generates severe economic losses for farmers. Our project aimed at characterising putative chemical signals used by this species, to develop new sustainable methods for population control that could also be used for this species protection in Great Britain. The water vole, a...
Article
Well-nourished spring-born female goats reach puberty in the autumn of the same year. Contrastingly, undernourished spring-born females reach puberty in the autumn of the following year. Therefore, in this study, we reared female goats (undernourished) under semi-extensive management and determined whether the introduction of photostimulated, sexua...
Article
Full-text available
Cervus nippon hider species maternal behaviour mother-young recognition parturition placentophagy species barrier young behaviour The removal of pre-existing geographical barriers between species, notably by humans, allows previously isolated species to hybridize. Interspecies hybridization has been studied at different levels but the mother-young...
Article
Full-text available
Background and purpose: We previously demonstrated that acetaminophen (AcAP) has to be metabolized in the brain by fatty acid amide hydrolase enzyme (FAAH) into AM404 (N-(4-hydroxyphenyl)-5Z,8Z,11Z,14Z-eicosatetraenamide) to recruit CB1 and TRPV1 receptors, responsible for its analgesic effect. However, the brain mechanisms supporting AcAP-induced...
Article
Full-text available
Background: Small ungulates (sheep and goat) display a seasonal breeding, characterised by two successive periods, sexual activity (SA) and sexual rest (SR). Odours emitted by a sexually active male can reactivate the ovulatory cycle of anoestrus females. The plasticity of the olfactory system under these hormonal changes has never been explored a...
Preprint
Full-text available
Background : Small ungulates (sheep and goat) display a seasonal breeding, characterised by two successive periods, sexual activity (SA) and sexual rest (SR). Odours emitted by a sexually active male can reactivate the ovulation of anoestrus females. The plasticity of the olfactory system under these hormonal changes has never been explored at the...
Preprint
Full-text available
Background : Small ungulates (sheep and goat) display a seasonal breeding, characterised by two successive periods, sexual activity (SA) and sexual rest (SR). Odours emitted by a sexually active male can reactivate the ovulation of anoestrus females. The plasticity of the olfactory system under these hormonal changes has never been explored at the...
Article
In seasonally anestrous goat does, ovulations can be induced by combining a treatment regimen including progestagen, eCG and prostaglandins. Nonetheless, ovulations occur only once and then does return to a seasonally anestrous state. This study was performed to determine whether the presence of a sexually active buck can stimulate a second ovulati...
Preprint
Background : Small ungulates (sheep and goat) display a seasonal breeding, characterised by two successive periods, sexual activity (SA) and sexual rest (SR). Odours emitted by a sexually active male can reactivate the ovulation of anoestrus females. The plasticity of the olfactory system under these hormonal changes has never been explored at the...
Conference Paper
In mid Jan, 40 ram‐lambs born in Oct were divided into 4 groups (n = 10): Group FA, exposed to 16 h of light for 2 months (15 Jan–15 Mar); Group SAR, housed with 3 adult sexually‐activated rams from 15 Mar to the end of the experiment; Group NAR, housed with 3 adult non‐activated rams from 15 Mar; and Group C, control, isolated from adult rams duri...
Conference Paper
In mid Jan, 40 ram‐lambs born in Oct were divided into 4 groups (n = 10): Group FA, exposed to 16 h of light for 2 months (15 Jan‐15 Mar); Group SAR, housed with 3 adult sexually‐activated rams from 15 Mar to the end of the experiment; Group NAR, housed with 3 adult non‐activated rams; and Group C, control, isolated from adult rams during the exper...
Article
New neurons are continuously added in the dentate gyrus of the hippocampus, the olfactory bulb and the hypothalamus of mammalian brain. In sheep, while the control of adult neurogenesis by the social environment or the photoperiod has been the subject of several studies, its regulation by intrinsic factors, like hormones or neurotransmitters is les...
Preprint
Background: Small ungulates (sheep and goat) display a seasonal breeding, characterised by two successive periods, sexual activity (SA) and sexual rest (SR). Odours emitted by a sexually active male can reactivate the ovulation of anoestrus females. The plasticity of the olfactory system under these hormonal changes has never been explored at the p...
Article
Goats are seasonal breeders with the main cue controlling the timing of breeding season being photoperiod. Hence, the season of birth impacts puberty onset: spring-born goats reach puberty in autumn, at 7 mo of age, whereas autumn-born goats reach puberty at 1 yr during the next reproductive season. The aim of this study was to determine whether ex...
Article
Full-text available
• Magnetic resonance imaging is a very powerful approach to perform anatomical and functional imaging explorations. • Large animal models are perfectly suited for MRI studies using clinical devices and these tools are currently being developed and improved. • Here we highlight an example of MRI to demonstrate the efficacy of gene therapy in sheep...
Article
The effect of the continuous presence of sexually active Rasa Aragonesa rams on the plasma luteinizing-hormone (LH) concentrations of ewes was studied from November to May. Light-treated rams were rendered sexually active (SA rams) by exposure to 2 months of artificially long days (16 h light/8 h dark) in one of two groups from either 1 November (S...
Article
Forty autumn-born ram-lambs were used to study the effect of several rearing strategies on their sexual activity and fertility at 8 months of age. The animals were assigned to one of the following four groups (n = 10): FA, which were exposed to 2 months of long days (15 January-15 March); SAR, which were housed with three Sexually Activated adult R...
Article
During pregnancy, the sequential release of progesterone, 17β-estradiol, prolactin, oxytocin and placental lactogens reorganize the female brain. Brain structures such as the medial preoptic area, the bed nucleus of the stria terminalis and the motivation network including the ventral tegmental area and the nucleus accumbens are reorganized by this...
Article
The present study evaluates the effects of adult exposure to low doses of a mixture of di-(2-ethylexyl)phthalate (DEHP) and nonylphenol (NP) on reproductive neuroendocrine function and behavior. The neural circuitry that processes male sexual behavior is tightly regulated by testosterone and its neural metabolite estradiol. In previous studies, we...
Article
In male goats, being in permanent visual contact with females in estrus does not prevent seasonal variation in certain endocrine hormone levels and sexual activities. In this study, we tested whether continuous and full contact with females in estrus prevented seasonal endocrinological variation in bucks. In 1 experiment (Exp. 1), we verified that...
Article
The aim of this study was to determine whether lower doses than 25 mg of progesterone reduce the frequency of short ovulatory cycles in seasonal anestrous goats exposed to sexually active bucks. Females from the control group were given an im dose of 2 mL olive oil (n = 9). Females from the experimental groups were given an im dose of 1 mg (n = 15)...
Article
Magnetic resonance imaging (MRI) is now widely used in equine veterinary practice. However, the mandatory European legislation regarding horse identification imposes the implantation of a transponder within the fatty tissue of the neck cervical ligament. While performing brain MRI for scientific purposes in ponies, we faced artifacts produced by su...
Article
Aggression is controlled by the olfactory system in many animal species. In male mice, territorial and infant-directed aggression are tightly regulated by the vomeronasal organ (VNO), but how diverse subsets of sensory neurons convey pheromonal information to limbic centers is not yet known. Here, we employ genetic strategies to show that mouse vom...
Article
Full-text available
The exposure of adult, female, Mediterranean goats during anoestrus to males with induced sexual activity via photostimulation, induces a very high percentage of ovulations. The present work examines the ability of photostimulated bucks to improve the male effect-induced reproductive response of young does over that induced by non-stimulated bucks....
Article
Seasonality of breeding has major technical and economical consequences in farms. The “male effect” is known to be a sustainable technique to induce out-of-season fertility but with variable results depending on breed and time in the year. Recently, we showed the high efficiency of light-treated rams and bucks to dramatically increase the efficienc...
Article
Full-text available
Both systemic and local production contribute to the concentration of steroids measured in the brain. This idea was originally based on rodent studies and was later extended to other species including humans and birds. In quail, a widely used model in behavioral neuroendocrinology, it was demonstrated that all enzymes needed to produce sex steroids...
Article
In rodents, early exposure to adult male is well known to induce an early puberty in females (Vandenbergh effect). This phenomenon has been less studied in other mammals. In goats, despite our extensive knowledge about the "male-effect" phenomenon in adults (i.e. ovulation induced by the introduction of the male during the anestrous), there are few...
Conference Paper
Full-text available
Nous avons étudié, par enregistrement vidéo et dans des conditions commerciales d’élevage (Salamanque, Espagne), les différences de comportement sexuel de béliers stimulés par deux mois de jours longs (16h de lumière par jour en novembre et décembre) (L, n=3) et de béliers contrôles, non stimulés (C, n=2), préalablement isolés des brebis. Les bélie...
Conference Paper
Full-text available
Au cours des mois de novembre et décembre, 6 béliers furent soumis à un traitement de jours longs (16 heures de lumière/ jour) (L) dans un élevage situé à Zamora (Espagne). Cinq béliers, dans des conditions naturelles d’illumination, forment le groupe contrôle (C). Le 1er février, il a été formé 3 lots de 30 brebis, dans lesquels ont été introduit...
Article
Most goats exposed to males in confined conditions have short ovulatory cycles. The frequency of these cycles can be reduced with a progesterone treatment prior to the introduction of males. The objective of this study was to determine whether extensive management conditions modify the frequency of short ovulatory cycles in progesterone-treated doe...
Conference Paper
Full-text available
Seasonality of breeding is an historical trait of temperate and subtropical sheep and goats, which has major technical and economical consequences in farms. In males and females, photoperiod imposes the sexual rest and cessation of ovulatory and oestrus activities in spring and summer in breeds of these latitudes. Recently, we showed the high e...
Presentation
Full-text available
Identification of chemosignals from lateral scent glands and urine of Arvicola terrestris
Conference Paper
Seasonality of breeding has major technical and economical consequences in farms. The “male effect” is known to be a sustainable technique to induce out-of-season fertility but with variable results depending on breed and time in the year. Recently, we showed the high efficiency of light-treated rams and bucks to dramatically increase the efficienc...
Article
Profound behavioral changes occur in the mother at parturition, a time when the maternal brain undergoes extensive remodeling of neural circuits, especially in olfactory structures. Adult neurogenesis, a form of brain plasticity, could constitute an adaptive response to motherhood. The present study hypothesized that chemical disruption of olfactor...
Article
Full-text available
The neural circuitry processing male sexual behavior is tightly regulated by testosterone and its neural metabolite estradiol. The present study evaluated the effects of adult exposure to low doses of nonylphenol (NP), a widespread environmental contaminant, on the neuroendocrine regulation of testosterone and expression of sexual behavior. Oral ex...
Article
Establishment of sexual dimorphisms in theadult mammalian brain and their maintenance by gonadalhormones are still unrevealed. In this study, we present acomprehensive morphological and functional MRI evalua-tion of brain sexual dimorphisms in adult sheep and the roleof adult gonadal secretions in the maintenance of thesedimorphisms.
Book
Être fier comme un paon ou chaud comme un lapin ou monté comme un cheval ! Autant d’expressions de bon ou mauvais goût qui témoignent de l’empreinte que les animaux et leurs comportements sexuels ont laissée dans notre imaginaire. Et il y a de quoi ! Car entre des poissons qui changent de sexe, des canards avec un zizi en tire-bouchon, des araignée...
Article
Full-text available
Background: Courtship behavior plays a critical role in attracting females and reproduction success. However, the effects of exposure to a ubiquitous contaminant di(2-ethylhexyl) phthalate (DEHP) on these behaviors and, in particular, on courtship vocalizations have not been examined. Objective: The effects of adult exposure to DEHP on courtship...
Article
Synopsis Males of many species rely on chemosensory information for social communication. In male Syrian hamsters (Mesocricetus auratus), as in many species, female chemosignals potently stimulate sexual behavior and a concurrent, rapid increase in circulating luteinizing hormone (LH) and testosterone (T). However, under winter-like, short-day (SD)...