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See detailThe neuroendocrinology of reproductive behavior in Japanese quail
Balthazart, Jacques ULg; Baillien, Michelle; Charlier, Thierry ULg et al

in Domestic Animal Endocrinology (2003), 25

Sex steroid hormones such as testosterone have widespread effects on brain physiology and function but one of their best characterized effects arguably involves the activation of male sexual behavior ... [more ▼]

Sex steroid hormones such as testosterone have widespread effects on brain physiology and function but one of their best characterized effects arguably involves the activation of male sexual behavior. During the past 20 years we have investigated the testosterone control of male sexual behavior in an avian species, the Japanese quail (Coturnix japonica).We briefly reviewhere the main features and advantages of this species relating to the investigation of fundamental questions in the field of behavioral neuroendocrinology, a field that studies inter-relationship among hormones, brain and behavior. Special attention is given to the intracellular metabolism of testosterone, in particular its aromatization into an estrogen, which plays a critical limiting role in the mediation of the behavioral effects of testosterone. Brain aromatase activity is controlled by steroids which increase the transcription of the enzyme, but afferent inputs that affect the intraneuronal concentrations of calcium also appear to have a pronounced effect on the enzyme activity through rapid changes in its phosphorylation status. The physiological significance of these slowgenomic and rapid, presumably non-genomic, changes in brain aromatase activity are also briefly discussed. [less ▲]

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See detailNeuroendocrinology of song behavior and avian brain plasticity: Multiple sites of action of sex steroid hormones
Ball, G. F.; Riters, L. V.; Balthazart, Jacques ULg

in Frontiers in Neuroendocrinology (2002), 23(2), 137-178

Seasonal changes in the brain of songbirds are one of the most dramatic examples of naturally occuring neuroplasticity that have been described in any vertebrate species. In males of temperate-zone ... [more ▼]

Seasonal changes in the brain of songbirds are one of the most dramatic examples of naturally occuring neuroplasticity that have been described in any vertebrate species. In males of temperate-zone songbird species, the volumes of several telencephalic nuclei that control song behavior are significantly larger in the spring than in the fall. These increases in volume are correlated with high rates of singing and high concentrations of testosterone in the plasma. Several song nuclei express either androgen receptors or estrogen receptors, therefore it is possible that testosterone acting via estrogenic or androgenic metabolites regulates song behavior by seasonally modulating the morphology of these song control nuclei. However, the causal links among these variables have not been established. Dissociations among high concentrations of testosterone, enlarged song nuclei, and high rates of singing behavior have been observed. Singing behavior itself can promote cellular changes associated with increases in the volume of the song control nuclei. Also, testosterone may stimulate song behavior by acting in brain regions outside of the song control system such as in the preoptic area or in catecholamine cell groups in the brainstem. Thus testosterone effects on neuroplasticity in the song system may be indirect in that behavioral activity stimulated by testosterone acting in sites that promote male sexual behavior could in turn promote morphological changes in the song system. (C) 2002 Elsevier Science (USA). [less ▲]

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See detailNeuroendocrinology of the thymus
Geenen, Vincent ULg; Robert, Françoise; Defresne, Marie-Paule ULg et al

in Hormone Research (1989), 31(1-2), 81-84

The neuropeptides oxytocin (OT) and vasopressin (VP) are synthesized in the human thymus in a similar way as in the hypothalamo-neurophypophyseal system. Immunocytochemistry with polyclonal and monoclonal ... [more ▼]

The neuropeptides oxytocin (OT) and vasopressin (VP) are synthesized in the human thymus in a similar way as in the hypothalamo-neurophypophyseal system. Immunocytochemistry with polyclonal and monoclonal antibodies revealed that immunoreactive OT- and VP-producing cells are localized in the subcapsular cortex and medulla of human and murine thymuses. The epithelial nature of the neuroendocrine thymic cells is demonstrated by their immunostaining with a monoclonal antibody against cytokeratin. An original example of a neuroendocrine-immune microenvironment is given by the thymic nurse cells which are composed of a large neuroendocrine epithelial cell enclosing numerous mitotic immature thymocytes. These observations and the previously reported mitogenic and immunomodulatory properties of VP and OT upon mature T cells and thymocytes strongly support the existence of a neuroendocrine thymo-lymphoid axis and an active role of thymic VP and OT in T cell differentiation and activation. [less ▲]

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See detailNeuroendocrinology of the thymus
Geenen, Vincent ULg; Robert, Françoise; Martens, Henri ULg et al

in Geenen, Vincent; Maggi, Mario (Eds.) Horizons in Endocrinology, Volume 2 (1991)

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See detailNeuroendocrinology of the thymus
Geenen, Vincent ULg

Conference given outside the academic context (1988)

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See detailNeuroendocrinology of the thymus
Geenen, Vincent ULg

Conference (1989, April)

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See detailNeuroendocrinology of the thymus
Geenen, Vincent ULg; Legros, Jean-Jacques ULg; Franchimont, Paul

Conference (1987, June 22)

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See detailNeuroestrogens Rapidly Regulate Sexual Motivation But Not Performance
Seredynski, Aurore ULg; Balthazart, Jacques ULg; Christophe, Virginie et al

in Journal of Neuroscience (2013), 33(1), 164-174

Estrogens exert pleiotropic effects on reproductive traits, which include differentiation and activation of reproductive behaviors and the control of the secretion of gonadotropins. Estrogens also ... [more ▼]

Estrogens exert pleiotropic effects on reproductive traits, which include differentiation and activation of reproductive behaviors and the control of the secretion of gonadotropins. Estrogens also profoundly affect non-reproductive traits, such as cognition and neuroprotection. These effects are usually attributed to nuclear receptor binding and subsequent regulation of target gene transcription. Estrogens also affect neuronal activity and cell-signaling pathways via faster, membrane-initiated events. How these two types of actions that operate in distinct timescales interact in the control of complex behavioral responses is poorly understood. Here, we show that the central administration of estradiol rapidly increases the expression of sexual motivation, as assessed by several measures of sexual motivation produced in response to the visual presentation of a female but not sexual performance in male Japanese quail. This effect is mimicked by membrane-impermeable analogs of estradiol, indicating that it is initiated at the cell membrane. Conversely, blocking the action of estrogens or their synthesis by a single intracerebroventricular injection of estrogen receptor antagonists or aromatase inhibitors, respectively, decreases sexual motivation within minutes without affecting performance. The same steroid has thus evolved complementary mechanisms to regulate different behavioral components (motivation vs performance) in distinct temporal domains (long- vs short-term) so that diverse reproductive activities can be properly coordinated to improve reproductive fitness. Given the pleiotropic effects exerted by estrogens, other responses controlled by these steroids might also depend on a slow genomic regulation of neuronal plasticity underlying behavioral activation and an acute control of motivation to engage in behavior. [less ▲]

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See detailNeurofibromatose de type 1
Hermanns-Lê, Trinh ULg; Devillers, Céline ULg; Franchimont, Claudine ULg et al

in Revue Médicale de Liège (2009), 64

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See detailLa neurogenese adulte ou l'histoire d'un dogme qui s'ecroule.
Pirotte, Dorothée ULg; Rogister, Bernard ULg

in Revue Médicale de Liège (2008), 63(5-6), 245-50

The history of sciences is characterized by major discoveries, but also by challenges of theories or dogma previously established and accepted by everybody. One of the recent examples illustrating such a ... [more ▼]

The history of sciences is characterized by major discoveries, but also by challenges of theories or dogma previously established and accepted by everybody. One of the recent examples illustrating such a questioning relates to the demonstration of the persistence of a cerebral neurogenesis in the adult brain, including in human. This adult neurogenesis is however limited, both in space (it concerns only the subventricular zone and the gyrus dentatus in the hippocampus) and the type of newly-formed neurons (interneurones which most of them are GABAergic and present respectively in the olfactive bulb and CA1 area of the hippocampus). Moreover, this neurogenesis does not seem to be recruited after a brain lesion, a situation which explains why functional recovery when it is observed remains a consequence of brain plasticity. We thus legitimately address the question about the physiological role of this adult brain neurogenesis as well as a possible implication in the aetiology of various neurological disorders, like the neurodegenerative diseases or epilepsy, but also in psychiatric diseases like depression. [less ▲]

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See detailNeurogenic Inflammation
Chavarria Bolanos, Daniel ULg

Scientific conference (2010, October 21)

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See detailNeurogenin 2 controls cortical neuron migration through regulation of Rnd2.
Heng, Julian Ik-Tsen; Nguyen, Laurent ULg; Castro, Diogo S et al

in Nature (2008), 455(7209), 114-8

Motility is a universal property of newly generated neurons. How cell migration is coordinately regulated with other aspects of neuron production is not well understood. Here we show that the proneural ... [more ▼]

Motility is a universal property of newly generated neurons. How cell migration is coordinately regulated with other aspects of neuron production is not well understood. Here we show that the proneural protein neurogenin 2 (Neurog2), which controls neurogenesis in the embryonic cerebral cortex, directly induces the expression of the small GTP-binding protein Rnd2 (ref. 3) in newly generated mouse cortical neurons before they initiate migration. Rnd2 silencing leads to a defect in radial migration of cortical neurons similar to that observed when the Neurog2 gene is deleted. Remarkably, restoring Rnd2 expression in Neurog2-mutant neurons is sufficient to rescue their ability to migrate. Our results identify Rnd2 as a novel essential regulator of neuronal migration in the cerebral cortex and demonstrate that Rnd2 is a major effector of Neurog2 function in the promotion of migration. Thus, a proneural protein controls the complex cellular behaviour of cell migration through a remarkably direct pathway involving the transcriptional activation of a small GTP-binding protein. [less ▲]

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See detailNeurohypophyseal response to apomorphine and clonidine stimulation in major depression
Scantamburlo, Gabrielle ULg; Fuchs, Sonia; Pitchot, William ULg et al

in European Neuropsychopharmacology (2004, October), 14(Suppl. 3), 291-292

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See detailNeurohypophysial peptides stimulate the phosphorylation of pre-T cell focal adhesion kinases
Martens, Henri ULg; Kecha, Ouafae; Charlet-Renard, Jeanne de Chantal ULg et al

in Neuroendocrinology (1998), 67(4), 282-289

Thymic oxytocin (OT) behaves as a cryptocrine signal targeted at the outer surface of thymic epithelial cell plasma membrane from where OT is able to interact with neurohypophysial peptide receptors ... [more ▼]

Thymic oxytocin (OT) behaves as a cryptocrine signal targeted at the outer surface of thymic epithelial cell plasma membrane from where OT is able to interact with neurohypophysial peptide receptors expressed by pre-T cells. Immature T cells bear a receptor of the V1 subtype, while OT receptors are predominantly expressed by cytotoxic CD8+ lymphocytes. In both T cell types, neurohypophysial peptide receptors transduce OT via the phosphoinositide pathway. Protein tyrosine phosphorylation is an early event of T cell activation. Western blots of murine pre-T cells (RL12-NP line) proteins probed with anti-phosphotyrosine (PY-20) revealed a great number of proteins the phosphorylation of which increased either with OT or vasopressin treatment. Two were immunoprecipitated with anti-focal adhesion kinase (FAK) mAb 2A7 and were identified one as p125FAK and the other as a coprecipitating 130-kDa protein. The p125FAK is connected to the Ras/MAPK pathway and is also implicated in TCR/CD3 signalling in T cell. Another protein phosphorylated by OT in RL12-NP was identified as paxillin, a 68-kDa protein localised at focal adhesion sites and associated with p 125FAK. These results indicate that phosphorylation of focal adhesion kinase may be induced in pre-T cell by thymic OT. [less ▲]

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See detailNeurohypophysial Receptor Gene Expression by Thymic T Cell Subsets and Thymic T Cell Lymphoma Cell Lines
Hansenne, Isabelle ULg; Rasier, G.; Charlet-Renard, C. et al

in Clinical & Developmental Immunology (2004), 11(1), 45-51

Neurohypophysial oxytocin (OT) and vasopressin (VP) genes are transcribed in thymic epithelium, while immature T lymphocytes express functional neurohypophysial receptors. Neurohypophysial receptors ... [more ▼]

Neurohypophysial oxytocin (OT) and vasopressin (VP) genes are transcribed in thymic epithelium, while immature T lymphocytes express functional neurohypophysial receptors. Neurohypophysial receptors belong to the G protein-linked seven-transmembrane receptor superfamily and are encoded by four distinct genes, OTR, V1R, V2R and V3R. The objective of this study was to identify the nature of neurohypophysial receptor in thymic T cell subsets purified by immunomagnetic selection, as well as in murine thymic lymphoma cell lines RL12-NP and BW5147. OTR is transcribed in all thymic T cell subsets and T cell lines, while V3R transcription is restricted to CD4+CD8+ and CD8+ thymic cells. Neither V1R nor V2R transcripts are detected in any kind of T cells. The OTR protein was identified by immunocytochemistry on thymocytes freshly isolated from C57BL/6 mice. In murine fetal thymic organ cultures, a specific OTR antagonist does not modify the percentage of T cell subsets, but increases late T cell apoptosis further evidencing the involvement of OT/OTR signaling in the control of T cell proliferation and survival. According to these data, OTR and V3R are differentially expressed during T cell ontogeny. Moreover, the restriction of OTR transcription to T cell lines derived from thymic lymphomas may be important in the context of T cell leukemia pathogenesis and treatment. [less ▲]

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See detailNeuroimaging after coma.
Tshibanda, Luaba ULg; Vanhaudenhuyse, Audrey ULg; Boly, Mélanie ULg et al

in Neuroradiology (2010), 52(1), 15-24

Following coma, some patients will recover wakefulness without signs of consciousness (only showing reflex movements, i.e., the vegetative state) or may show non-reflex movements but remain without ... [more ▼]

Following coma, some patients will recover wakefulness without signs of consciousness (only showing reflex movements, i.e., the vegetative state) or may show non-reflex movements but remain without functional communication (i.e., the minimally conscious state). Currently, there remains a high rate of misdiagnosis of the vegetative state (Schnakers et. al. BMC Neurol, 9:35, 8) and the clinical and electrophysiological markers of outcome from the vegetative and minimally conscious states remain unsatisfactory. This should incite clinicians to use multimodal assessment to detect objective signs of consciousness and validate para-clinical prognostic markers in these challenging patients. This review will focus on advanced magnetic resonance imaging (MRI) techniques such as magnetic resonance spectroscopy, diffusion tensor imaging, and functional MRI (fMRI studies in both "activation" and "resting state" conditions) that were recently introduced in the assessment of patients with chronic disorders of consciousness. [less ▲]

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See detailNeuroimaging in Disorders of Consciousness
Bodart, Olivier ULg; Charland-Verville, Vanessa ULg; Laureys, Steven ULg et al

in Filippi, M. (Ed.) Oxford Textbook of Clinical Neurology (2014)

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See detailNeuroimaging in Sleep and Sleep Disorders
Desseilles, Martin ULg; Dang Vu, Thien Thanh ULg; Schwartz, Sophie et al

in Chokroverty, Sudhansu (Ed.) Sleep Disorders Medicine (2009)

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See detailNeuroimaging in sleep medicine.
Dang Vu, Thien Thanh ULg; Desseilles, Martin ULg; Petit, Dominique ULg et al

in Sleep Medicine (2007), 8(4), 349-72

The development of neuroimaging techniques has made possible the characterization of cerebral function throughout the sleep-wake cycle in normal human subjects. Indeed, human brain activity during sleep ... [more ▼]

The development of neuroimaging techniques has made possible the characterization of cerebral function throughout the sleep-wake cycle in normal human subjects. Indeed, human brain activity during sleep is segregated within specific cortical and subcortical areas in relation to the sleep stage, sleep physiological events and previous waking activity. This approach has allowed sleep physiological theories developed from animal data to be confirmed, but has also introduced original concepts about the neurobiological mechanisms of sleep, dreams and memory in humans. In contrast, at present, few neuroimaging studies have been dedicated to human sleep disorders. The available work has brought interesting data that describe some aspects of the pathophysiology and neural consequences of disorders such as insomnia, sleep apnea and narcolepsy. However, the interpretation of many of these results is restricted by limited sample size and spatial/temporal resolution of the employed technique. The use of neuroimaging in sleep medicine is actually restrained by concerns resulting from the technical experimental settings and the characteristics of the diseases. Nevertheless, we predict that future studies, conducted with state of the art techniques on larger numbers of patients, will be able to address these issues and contribute significantly to the understanding of the neural basis of sleep pathologies. This may finally offer the opportunity to use neuroimaging, in addition to the clinical and electrophysiological assessments, as a helpful tool in the diagnosis, classification, treatment and monitoring of sleep disorders in humans. [less ▲]

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