Littérature scientifique sur le sujet « Median raphe region »

Median raphe cysts present anywhere between the external urethral meatus and the anus. The cysts can occur at parameatus, glans penis, penile shaft, scrotum, or perineum. Perianal region is an extremely rare location for these lesions. Here we present a 50-year-old male patient who presented with a cystic, fluctuant lesion, located at 12 o’clock in perianal region. Microscopic examination revealed a cystic lesion with keratinized and nonkeratinized stratified squamous epithelium, pseudostratified ciliated epithelium, and scattered goblet cells. The final diagnosis of the lesion was median raphe cyst. Ciliated cells and perianal localization in median raphe cysts are extremely rare characteristics.

Hippocampal EEG, GABAergic interneurons, and principal cells were recorded simultaneously as rats foraged within one of three environments both before and after modulation of serotonergic inputs to the hippocampus. Median raphe microinjections of the 5-HT1a receptor agonist 8-OH-DPAT were made to produce inhibition of serotonergic neurons in this region. Such microinjections produced behavioral arousal and increases in the amplitude of hippocampal EEG theta. Consistent with the pattern of serotonergic innervation of the hippocampus, the GABAergic interneuron population was affected differentially by the microinjections. Principal cells were generally unaffected by the manipulation and maintained robust spatial firing correlates within the foraging environment. The results provide basic data on the relationship between serotonergic median raphe neurons and hippocampal activity in a behaving animal. The data suggest that behavioral responses to manipulation of the serotonergic system are mediated by brain regions other than the hippocampus or are mediated through changes in the activity of hippocampal interneurons.

Adverse events need to be quickly evaluated and memorized, yet how these processes are coordinated is poorly understood. We discovered a large population of excitatory neurons in mouse median raphe region (MRR) expressing vesicular glutamate transporter 2 (vGluT2) that received inputs from several negative experience–related brain centers, projected to the main aversion centers, and activated the septohippocampal system pivotal for learning of adverse events. These neurons were selectively activated by aversive but not rewarding stimuli. Their stimulation induced place aversion, aggression, depression-related anhedonia, and suppression of reward-seeking behavior and memory acquisition–promoting hippocampal theta oscillations. By contrast, their suppression impaired both contextual and cued fear memory formation. These results suggest that MRR vGluT2 neurons are crucial for the acquisition of negative experiences and may play a central role in depression-related mood disorders.

We have studied the effects, in the conscious rat, of electrical stimulation of the dorsal or median raphe nuclei on integrated functional activity, as assessed by the quantitative 2-deoxyglucose autoradiographic technique, Stimulation of serotonergic neurons elicits metabolic changes in cortical and thalamic regions that are not limited to those structures known to receive the densest serotonergic innervation. The thalamic nuclei that are activated by raphe stimulation include those that subserve the processing of somesthetic, accessory visual, and limbic information, Raphe stimulation increased cortical glucose use in a laminar and columnar pattern, but only in a highly circumscribed region that corresponds to the somatotopic representation of the rat's face and head. These findings indicate that ascending serotonergic neurons play an important modulatory role in the regulation of thalamocortical glucose use, observations that may be of value in the understanding of the etiology and expression of classic migraine.

Background.Histopathological alterations can arise when the denture-supporting mucosa experiences microbial and mechanical stress through the denture base and diagnosis of these diseases usually follows microvascular changes. Microcirculation measurement could allow for detection of such dysfunction and aid in the early diagnosis of palatal mucosa pathologies.Materials and Methods. We tested the sensitivity of laser Doppler for measuring the microcirculation of the palatal mucosa, assessing the median raphe (MR), Schroeder area (SA), and retroincisive papilla (RP). A Doppler PeriFlux 5000 System, containing a laser diode, was used. 54 healthy participants were recruited. We compare the measurements of PU (perfusion unit) using ANOVA test.Results.The numerical values for palatal mucosa blood flow differed significantly among the anatomical areas (p=0.0167). The mean value of Schroeder area was 92.6 (SD: 38.4) and was significantly higher than the retroincisive papilla (51.9) (SD: 20.2) (p<0.05), which in turn was higher than that of median raphe (31.9) (SD: 24.2) (p<0.0001).Conclusion.Schroeder area appeared to have the greatest sensitivity, and vascular flow variability among individuals was also greatest in this region. We suggest that analysis of blood stream modification with laser Doppler of the palatal mucosa can help to detect onset signs of pathological alterations.

Dans le système nerveux central, les neurones glutamatergiques sont caractérisés par les transporteurs vésiculaires de glutamate (VGLUT). VGLUT3 est le transporteur le plus récemment identifié, et pour lequel l’implication dans les processus physiologiques et comportementaux est encore peu caractérisée. Dans la région du raphé médian (MRR), une quantité surprenante de neurones VGLUT3+ est observée, à la fois dans des cellules apparemment purement glutamatergiques mais également dans des cellules sérotoninergiques. Bien que VGLUT3 soit présent dans des régions clés telles que le cortex préfrontal, l'hippocampe et d'autres noyaux du raphé, peu d’études ont été menées sur son implication sur les comportements sociaux, ou les processus d'apprentissage et de mémoire. En outre, le MRR (et ses neurones VGLUT3+) se projette également dans ces zones et peut potentiellement affecter tous ces comportements. L'objectif de cette thèse était donc de compléter la littérature actuelle sur le rôle du VGLUT3 dans les processus d’apprentissage et de mémoire à l'aide de souris invalidées en VGLUT3 (knock-out; VGLUT3 KO). Une sous-population spécifique du MRR a été ciblée grâce à l’utilisation d’une lignée de souris transgéniques VGLUT3-Cre couplée à de la chémogénétique ou de l'optogénétique. Des paradigmes comportementaux ont été menés sur ces deux modèles VGLUT3 KO et VGLUT3-Cre afin d'analyser en détail le comportement social, la locomotion et le comportement de type anxieux. L'hippocampe étant riche en neurones VGLUT3+ et en afférences MRR-VGLUT3+, l'apprentissage et la mémoire spatiale ont également été étudiés. En outre, des techniques moléculaires ont été utilisées pour valider et confirmer l'expression de l'ARNm VGLUT3 dans le MRR chez la souris et l'humain, la libération de divers neurotransmetteurs du MRR dans l'hippocampe et la chémogénétique nouvellement introduite. Les résultats montrent que l'ablation totale du gène VGLUT3 non seulement augmente le comportement social, mais semble également entraîner une augmentation des comportements agressifs dans des contextes anxiogènes. Nous avons par ailleurs confirmé le phénotype anxieux des souris VGLUT3 KO et une altération de leur mémoire sociale à long terme. En revanche, il semble que l’absence de VGLUT3 n'altère pas de manière significative l'apprentissage et la mémoire spatiale. Dans le cas des neurones MRR-VGLUT3, nous avons découvert qu'ils pouvaient potentiellement jouer un rôle dans la locomotion et l'intérêt social à long terme, tout en affectant le comportement social amical d'une manière spécifique au contexte. L'excitation chronique des neurones MRR-VGLUT3 a facilité la formation de la mémoire chez les souris dans une tâche de mémoire spatiale dépendante de l'hippocampe. En outre, nous avons confirmé que dans le MRR, seule une minorité (~20%) de neurones VGLUT3+ co-expriment un phénotype sérotoninergique. Comme chez les rongeurs, les noyaux du raphé chez les humains (parmi d'autres régions du tronc cérébral) expriment également VGLUT3, nos résultats peuvent donc potentiellement avoir une pertinence clinique à l'avenir
In the central nervous system, glutamatergic neurons are characterised by the expression of vesicular glutamate transporters (VGLUTs). The newest member of this protein family is VGLUT3, which role in behaviour and physiology is still being characterised. Moreover, in the median raphe region (MRR), there is a surprising amount of VGLUT3+ neurons, either purely glutamatergic, or within serotonergic neurons. Although VGLUT3 is found in key areas like the prefrontal cortex, hippocampus and other raphe nuclei, not much is known about its effects on behaviours, such as social behaviour, learning or memory processes. Additionally, MRR (and its VGLUT3+ neurons) also project to these areas, and potentially affect all these behaviours. Thus, the goal of this PhD was to complement current literature on the role of VGLUT3 in behaviour with the help of VGLUT3 knockout (KO) mice. Specific subpopulation in the MRR was targeted by transgenic VGLUT3-Cre mouse line, chemogenetics and optogenetics. Behaviour paradigms were conducted in both VGLUT3 KO and VGLUT3-Cre strains to analyse social behaviour in great details and to control for possible confounding factors of locomotion and anxiety-like behaviour. Then, as the hippocampus is rich in both VGLUT3+ neurons and MRR-VGLUT3 afferents, a classical hippocampus-based spatial learning and memory test, the Morris water maze was also investigated. Additionally, molecular technics were also utilised to validate and confirm VGLUT3 mRNA expression in the MRR in mice and humans, MRR neurotransmitter release in the hippocampus, and the propriety of the newly introduced chemogenetics. Results show that the total ablation of the VGLUT3 gene shifted the behaviour to be socially more active but seems to result in an inadequate appearance of aggression in anxiogenic contexts. We further confirmed the highly anxious phenotype and the long-term social memory impairment of the VGLUT3 KO animals. On the other hand, it seems like this lifelong, complete deficiency does not significantly impair spatial learning and memory. In the case of MRR-VGLUT3 neurons, we found that they could potentially play a role in locomotion and long-term social interest, while affecting friendly social behaviour in a context specific manner. Chronic, chemogenetic excitation of the MRR-VGLUT3 neurons facilitated memory formation in mice in a hippocampus dependent spatial memory task. Additionally, we confirmed that in the MRR only a minority (~20%) of VGLUT3+ neurons co-express a serotonergic phenotype. Similarly to rodents, human raphe nuclei (among other brainstem areas) also express VGLUT3, thus, our results can potentially have clinical relevance in the future

Abstract Longitudinal sections through the medulla and cervical spinal cord of small mammals demonstrate that the ventral funiculus of the spinal cord lies mainly ventral to the caudal end of the inferior olive, and that it continues on in the medulla as fibers associated with the medial or white reticular formation. The latest evidence about this continuity is presented in Fig. 409, which is from a sagittal section through the medulla of a newborn mouse. The most ventrolateral region of the ventral funiculus follows this course, and is particularly obviou,s around lateral parts of the inferior olive. In contrast, dorsomedial parts of the ventral funiculus are continuous with the medial longitudinal fascicle and with fibers in regions of the medial or white reticular formation dorsal to the inferior olive. In the mouse, rabbit, cat, and so on, some bundles of the ventral funiculus also course near the raphe, between the inferior olive dorsally and the pyramidal tract ventrally.

The vestibulocerebellum consists of the flocculus, ventral paraflocculus, nodulus, and uvula. ■ The flocculus receives inputs from the vestibular nucleus and nerve, nucleus prepositus hypoglossi (NPH), inferior olivary nucleus, cell groups of the paramedian tracts (PMT), nucleus reticularis tegmenti pontis (NRTP), and mesencephalic reticular formation. ■ The ventral paraflocculus receives inputs from contralateral pontine nuclei. ■ Project to ipsilateral superior and medial vestibular nuclei, and the y-group ■ Receive input from the medial and inferior vestibular nuclei, vestibular nerve, NPH, and inferior olivary nucleus ■ Project to the vestibular nuclei ■ The oculomotor vermis consists of parts of the declive, folium, tuber, and pyramis. ■ Receives inputs from the inferior olivary nucleus, vestibular nuclei, NPH, paramedian pontine reticular formation (PPRF), NRTP, and dorsolateral and dorsomedial pontine nuclei ■ Projects to the caudal fastigial nucleus ■ Stimulation of the Purkinje cells in the dorsal vermis elicits contralaterally directed saccades and smooth pursuit ■ Receives inputs from the dorsal vermis, inferior olivary nucleus, and NRTP ■ Decussates and projects via the uncinate fasciculus of the brachium conjunctivum to the contralateral PPRF, rostral interstitial nucleus of the medial longitudinal fasciculus, nucleus of the posterior commissure, omnipause neurons in nucleus raphe interpositus, the mesencephalic reticular formation, and superior colliculus ■ Neurons in the fastigial oculomotor region (FOR) fire during both ipsilateral and contralateral saccades. 1. The contralateral FOR neurons burst before the onset of saccade, and the onset of firing is not correlated with any property of the saccade. 2. Conversely, the time of onset for neurons in the ipsilateral FOR varies, with bursts occurring later for larger saccades. 3. Thus, the difference in time of onset between contralateral and ipsilateral FOR activity encodes the amplitude of saccades (i.e., the larger the difference in time of onset, the larger the saccade amplitude). Eye movement abnormalities in uncinate fasciculus lesion include hypometric ipsilesional saccades and hypermetric contralesional saccades (“contrapulsion”). Arnold-Chiari malformation is a malformation of the medullary–spinal junction with herniation of intracranial contents through the foramen magnum. The three types are illustrated in the figure below.