Activation of 5-HT3 receptors in the medulla oblongata is involved in the phasic control of urinary bladder.

The control of micturition depends on reflex mechanisms, however, it undergoes modulation from cortex, pons and medullary areas. This study investigated if the activation of 5-HT3 receptors in the medulla influences the urinary bladder (UB) regulation in rats. Isoflurane female Wistar rats were submitted to catheterization of the femoral artery and vein for mean arterial pressure (MAP) and heart rate (HR) recordings and injection of drugs, respectively. The UB was cannulated for intravesical pressure (IP) measurement. The Doppler flow probe was placed around the left renal artery for renal conductance (RC) recordings. Phenylbiguanide (PB) and granisetron (GN) were injected into the 4th brain ventricle in rats with guide cannulas implanted 5 days prior to the experiments; or PB and GN were randomly injected intravenously or applied topically (in situ) on the UB. PB injection into 4th V significantly increased IP (68.67 ± 11.70%) and decreased MAP (-29 ± 6 mmHg) compared to saline (0.34 ± 0.64% and -2 ± 2 mmHg), with no changes in the HR and RC. GN injection into the 4th V did not significantly change the IP and RC compared to saline, nevertheless, significantly increased MAP (25 ± 4 mmHg) and heart rate (36 ± 9 bpm) compared to saline. Intravenous PB and GN only produced cardiovascular effects, whilst PB but not GN in situ on the UB evoked increase in IP (111.60 ± 30.36%). Therefore, the activation of 5HT-3 receptors in medullary areas increases the intravesical pressure and these receptors are involved in the phasic control of UB. In contrast, 5-HT3 receptors in the medulla oblongata are involved in the pathways of the tonic control of the cardiovascular system. The activation of 5-HT3 receptors in the bladder cause increase in intravesical pressure and this regulation seem to be under phasic control as the blockade of such receptors elicits no changes in baseline intravesical pressure.

Measurement of CSF pulsation from EPI-based human fMRI.

It is recently discovered that the glymphatic system and meningeal lymphatic system are the primary routes for the clearance of brain waste products. The CSF flow is part of these systems, facilitating the clearance procedure. Nonetheless, the relationship between CSF flow and brain functional activity has been underexplored. To investigate CSF dynamics and functional brain activity simultaneously, recent studies have proposed a CSF inflow index measured on edge slices (CSFedge) of echo-planar imaging (EPI) based functional magnetic resonance imaging (fMRI), however, it lacks the quantitative aspect of the CSF pulsation. We proposed a new method for quantifying CSF pulsation (CSFpulse) based on an interslice CSF pulsation model in the 4th ventricle of EPI-based fMRI. The proposed CSFpulse successfully detected the higher CSF flow during the resting state than the typical task states (visual and motor) (p<.05), which is consistent with previous studies based on phase contrast (PC) MRI and CSF volume MRI, while it was not detected in CSFedge based indices or baseline CSF signals in various regions of interest (ROIs). Moreover, CSFpulse demonstrated dynamic functional changes in CSF pulsation: it decreased during the activation-on blocks while it increased during the activation-off blocks. CSFpulse significantly correlated with stroke volume measured using PC MRI, a standard method for CSF pulsation quantification, under the same functional state, while CSFedge based indices or CSF ROIs showed no correlation with the PC MRI stroke volume. Lastly, the correlation of CSFpulse with global BOLD was weaker than that of CSFedge, suggesting that CSFpulse may reflect distinct CSF physiological information that is less affected by global BOLD effects. Based on these results, the proposed CSFpulse provides CSF pulsatility information more accurately in a quantitative manner than CSFedge based indices from the recent CSF studies or the conventional ROI-based analysis. In addition to the high correlation with PC MRI, CSFpulse is much faster than PC MRI and provides information of functional brain activations simultaneously, advantageous over PC MRI or CSF volume MRI. Accordingly, the suggested CSFpulse can be used for investigating intra-subject functional changes in BOLD and CSF pulsation simultaneously and inter-subject CSF pulsation variations based on conventional EPI-based fMRI, which warrants further investigation.

Stereotactic surgery for neurocysticercosis of the 4th ventricle: illustrative cases.

BACKGROUND: Neurocysticercosis, caused by the larval stage of Taenia solium, affects the cerebral ventricles in 20-30% of cases and may lead to hydrocephalus and other neurological morbidity. Conventional treatment for cysts in the 4th ventricle includes open surgery (suboccipital approach) and neuroendoscopy, with the latter being the option of choice. Stereotactic surgery, minimally invasive, offers a good alternative for this type of deep lesion. OBSERVATIONS: The authors report the cases of two women, 30 and 45 years old, who presented with headache, dizziness, and ataxia and were diagnosed with 4th ventricle cysticercosis. Magnetic resonance imaging (MRI) revealed dilated 4th ventricles (approximately 2.5 cm in both cases, with cystic images inside the ventricular cavity). Both patients were treated with stereotactic surgery via a suboccipital transcerebellar approach. Cyst material was extracted, and the diagnosis was confirmed by pathological examination. The surgeries had no complications and resulted in clinical improvement. Control MRI scans showed reduction of the volume of the ventricle without residual cysts. LESSONS: Minimally invasive stereotactic surgery provided a safe alternative for 4th ventricle neurocysticercosis cysts, with more benefits than risks in comparison with conventional techniques.

Papiloma coroideo atípico en paciente de la tercera edad: Revisión bibliográfica a propósito de un caso / Atypical choroidal papilloma in an elderly patient: A literature review on a case

Introducción: Los tumores del plexo coroideo son raros. Contabilizan del 0,3 a 0,6% de la totalidad de los tumores cerebrales en adultos y del 10 a 20% en infantes; en quienes se ha registrado el 70% de estos y de los cuales al menos un 50% suceden en menores de dos años de edad. Objetivos: Esta publicación consiste en describir un caso de la tercera edad con papiloma atípico del cuarto ventrículo, la forma de resolución seleccionada y revisar la bibliografía del tema. Presentación del caso: Masculino de 71 años de edad que consulta por inestabilidad en la marcha y cefalea holocraneana intermitente. Al examen se muestra desorientado, con trastornos mnésicos, marcha magnética e incontinencia urinaria. Se realiza TC contrastada y posterior RM de cerebro con gadolinio objetivándose lesión espacio ocupante hipo-isointensa de 10 cc. Aprox. ocupando el 4to ventrículo, con realce intenso a la administración de contraste y ventriculomegalia asociada con edema transependimario. Intervención: Se realiza exéresis, logrando resección completa y mejoría clínica. Discusión: El papiloma atípico de plexo coroideo (Grado II) es una entidad intermedia que se distingue fundamentalmente del papiloma de grado I por su actividad mitótica; 2 o más mitosis en 10 campos. Conclusión: Este reporte, aborda una patología quirúrgicamente desafiante, potencialmente curable y clásicamente infantil, pero que también puede presentarse en la población geriátrica.

Introduction: Choroid plexus tumors are rare. They account for 0.3 to 0.6% of all brain tumors in adults and 10 to 20% in infants; in whom 70% of these have been registered and of which at least 50% occur in children under two years of age. Objectives: This publication consists of describing a case of the third age with atypical papilloma of the fourth ventricle, the selected form of resolution and reviewing the bibliography on the subject. Case presentation: 71-year-old male who consulted for gait instability and intermittent holocranial headache. On examination, he was disoriented, with memory disorders, magnetic gait, and urinary incontinence. Contrast-enhanced CT and subsequent MRI of the brain with gadolinium were performed, showing a 10 cc hypo-isointense occupying space lesion. Approx. occupying the 4th ventricle, with intense enhancement to contrast administration and ventriculomegaly associated with transependymal edema. Intervention: Exeresis is performed, achieving complete resection and clinical improvement. Discussion: Atypical choroid plexus papilloma (Grade II) is an intermediate entity that is fundamentally distinguished from grade I papilloma by its mitotic activity; 2 or more mitoses in 10 fields. Conclusion: This report addresses a surgically challenging pathology, potentially curable and classically infantile, but which can also occur in the geriatric population.

iDISCO+ for the Study of Neuroimmune Architecture of the Rat Auditory Brainstem.

The lower stations of the auditory system display a complex anatomy. The inner ear labyrinth is composed of several interconnecting membranous structures encased in cavities of the temporal bone, and the cerebellopontine angle contains fragile structures such as meningeal folds, the choroid plexus (CP), and highly variable vascular formations. For this reason, most histological studies of the auditory system have either focused on the inner ear or the CNS by physically detaching the temporal bone from the brainstem. However, several studies of neuroimmune interactions have pinpointed the importance of structures such as meninges and CP; in the auditory system, an immune function has also been suggested for inner ear structures such as the endolymphatic duct (ED) and sac. All these structures are thin, fragile, and have complex 3D shapes. In order to study the immune cell populations located on these structures and their relevance to the inner ear and auditory brainstem in health and disease, we obtained a clarified-decalcified preparation of the rat hindbrain still attached to the intact temporal bone. This preparation may be immunolabeled using a clearing protocol (based on iDISCO+) to show location and functional state of immune cells. The observed macrophage distribution suggests the presence of CP-mediated communication pathways between the inner ear and the cochlear nuclei.

Fourth ventricle neurocysticercosis: Rigid endoscopic management. Description of direct transcerebellar approach.

BACKGROUND: Endoscopy has gained a crucial role in high specialty neurosurgery during the last decades. At present, there are well-defined flexible neuroendoscopic procedures to treat ventricular and subarachnoid space pathologies. Neurocysticercosis is recognized as a common cause of neurologic disease in developing countries and the United States. Surgical intervention, especially cerebrospinal fluid diversion, is the key for management of hydrocephalus. In 2002, a consensus suggested that ventricular forms should be treated with endoscopy as the first option. CASE DESCRIPTION: Here, we present the case of a 51-year-old right-handed male, from Estado de México. Two days before admission he experienced holocraneal headache 7/10 on the visual analogue scale which was intermittent, with no response to any medication, sudden worsening of pain to 10/10, nausea, and vomit. On physical examination, he presented with 14 points in the Glasgow coma scale (M6, O4, V4), pupils were 3 mm, there was adequate light-reflex response, and bilateral papilledema. The cranial nerves did not have other pathological responses, extremities had adequate strength of 5/5, and normal reflexes (++/++) were noted. Neuroimaging studies showed dilatation of the four ventricles as well as a cystic lesion in the fourth ventricle. Surgical position was Concorde, and the approach through a suboccipital burr hole was planned preoperatively with craneometric points. A rigid Karl Storz Hopkins II® endoscope was inserted directly through the cerebellum and the cystic lesion was extracted entirely. CONCLUSION: This article presents a useful technique with low morbidity and mortality. Further investigation is needed, especially in our Mexico, where neuroendoscopical techniques are still in the development phase.

MRI capture of intermittent ventriculomegaly in a patient with ventriculo-peritoneal shunt.

Intermittent change in ventricular size in patients with ventriculo-peritoneal shunts is a recognised complication but definitive imaging evidence is rare. We report a 3 years old boy with a medullary astrocytoma and ventriculo-peritoneal shunt placement who demonstrated intermittent ventriculomegaly during a single MRI scan.

Magendie and Luschka: Holes in the 4th ventricle.

Cerebrospinal fluid (CSF) is a complex liquid formed mainly by the choroid plexuses. After filling the ventricular system where it circulates, CSF flows out to the subarachnoid spaces through openings in the 4th ventricle. Following numerous studies on CSF pathways, these openings were first discovered in the 19th century by two notable researchers, François Magendie and Hubert von Luschka, who described the median and lateral openings subsequently named after them. Even after the studies of Axel Key and Gustav Magnus Retzius confirming these openings, their existence was questioned by many anatomists, yet acknowledged by others. Finally gaining the acceptance of all, recognition of the holes endures to the present day. Interest in these openings may be attributed to the several congenital or acquired pathological conditions that may affect them, usually associated with hydrocephalus. We report some historical aspects of these apertures and their discoverers.

O líquido cefalorraquidiano é um fluido complexo formado principalmente pelos plexos coroides que, após preencher o sistema ventricular, onde circula, flui para os espaços subaracnóides através de aberturas do 4o ventrículo. Antecedido por numerosos estudos sobre as vias do líquido cefalorraquidiano, estas aberturas foram descobertas pela primeira vez no século XIX graças a dois pesquisadores notáveis, François Magendie e Hubert von Luschka, que descreveram as aberturas mediana e laterais do 4o ventrículo, as quais receberam, então, seus nomes. Apesar dos estudos de Axel Key e Gustav Magnus Retzius que confirmaram a existência de tais aberturas, estas foram postas em dúvida por muitos anatomistas, mas aceitas por outros, para finalmente serem reconhecidas por todos, o que perdura até os presentes dias. O interesse por essas aberturas pode ser atribuído a diversas condições patológicas congênitas ou adquiridas que podem atingi-las, geralmente associadas à hidrocefalia. Aqui são relatados alguns aspectos históricos sobre essas aberturas e seus descobridores.

Co-localization of hypocretin-1 and leucine-enkephalin in hypothalamic neurons projecting to the nucleus of the solitary tract and their effect on arterial pressure.

Experiments were done to investigate whether hypothalamic hypocretin-1 (hcrt-1; orexin-A) neurons that sent axonal projections to cardiovascular responsive sites in the nucleus of the solitary tract (NTS) co-expressed leucine-enkephalin (L-Enk), and to determine the effects of co-administration of hcrt-1 and D-Ala2,D-Leu5-Enkephalin (DADL) into NTS on mean arterial pressure (MAP) and heart rate. In the first series, in the Wistar rat the retrograde tract-tracer fluorogold (FG) was microinjected (50nl) into caudal NTS sites at which L-glutamate (0.25 M; 10 nl) elicited decreases in MAP and where fibers hcrt-1 immunoreactive fibers were observed that also contained L-Enk immunoreactivity. Of the number of hypothalamic hcrt-1 immunoreactive neurons identified ipsilateral to the NTS injection site (1207 ± 78), 32.3 ± 2.3% co-expressed L-Enk immunoreactivity and of these, 2.6 ± 1.1% were retrogradely labeled with FG. Hcrt-1/L-Enk neurons projecting to NTS were found mainly within the perifornical region. In the second series, the region of caudal NTS found to contain axons that co-expressed hcrt-1 and L-Enk immunoreactivity was microinjected with a combination of hcrt-1 and DADL in α-chloralose anesthetized Wistar rats. Microinjection of DADL into NTS elicited depressor and bradycardia responses similar to those elicited by microinjection of hcrt-1. An hcrt-1 injection immediately after the DADL injection elicited an almost twofold increase in the magnitude of the depressor and bradycardia responses compared to those elicited by hcrt-1 alone. Prior injections of the non-specific opioid receptor antagonist naloxone or the specific opioid δ-receptor antagonist ICI 154,129 significantly attenuated the cardiovascular responses to the combined hcrt-1-DADL injections. Taken together, these data suggest that activation of hypothalamic-opioidergic neuronal systems contribute to the NTS hcrt-1 induced cardiovascular responses, and that this descending hypothalamo-medullary pathway may represent the anatomical substrate by which hcrt-1/L-Enk neurons function in the coordination of autonomic-cardiovascular responses during different behavioral states.

Plasma leptin inhibits the response of nucleus of the solitary tract neurons to aortic baroreceptor stimulation.

Leptin receptors have been identified within the nucleus of the solitary tract (NTS) and leptin injections into the caudal NTS inhibit the baroreceptor reflex. However, whether plasma leptin alters the discharge of NTS neurons mediating aortic baroreceptor reflex activity is not known. A series of electrophysiological single unit recording experiments was done in the urethane-chloralose anesthetized, paralyzed and artificially ventilated Wistar and Zucker obese rat with either their neuroaxis intact or with mid-collicular transections. Single units in NTS antidromically activated by electrical stimulation of depressor sites in the caudal ventrolateral medulla (CVLM) were found to display a cardiac cycle-related rhythmicity. These units were tested for their responses to stimulation of the aortic depressor nerve (ADN) and intra-carotid injections of leptin (50-200ng/0.1ml). Of 63 single units tested in NTS, 33 were antidromically activated by stimulation of CVLM depressor sites and 18 of these single units responded with a decrease in discharge rate after intracarotid injections of leptin. Thirteen of these leptin responsive neurons (∼72%) were excited by ADN stimulation. Furthermore, the excitatory response of these single units to ADN stimulation was attenuated by about 50% after the intracarotid leptin injection. Intracarotid injections of leptin (200ng/0.1ml) in the Zucker obese rat did not alter the discharge rate of NTS-CVLM projecting neurons. These data suggest that leptin exerts a modulatory effect on brainstem neuronal circuits that control cardiovascular responses elicited during the reflex activation of arterial baroreceptors.

Transient Mutism following Resection of 4th Ventricle Choroid Plexus Papilloma in a 6-Year-Old Girl

Transient mutism has ben known as a rare complication following a posterior fossa approach to cerebellar tumors, although its pathophysiology remains unclear. Cerebellar mutism may be defined as a transient mutism occurring after a posterior fossa tumor approach in children with unimpaired consciousness, unimpaired symbolic functions, no detectable deficit of cranial nerves or peripheral organs of speech, and no lesions of long pathways in the course of the cranial nerves at the level of the brain stem. Forty two cases in children, and only two cases in adults have been found in the literature. We report a case of transient mutism with oropharyngeal apraxia after total excision of 4th ventricle choroids plexus papilloma in a 6-year-old girl. Postoperatively, the patient became mute and refused food intake without disturbance of consciousness, or lower cranial nerve function. Computed tomography(CT) and magnetic resonance image(MRI) demonstrated no abnormal findings except the surgical lesion in the posterior fossa. The mutism lasted for 3 weeks, but she gradually became fluent. The mechanism of "cerebellar mutism" is briefly discussed with literature review.

Two Cases of Choroid Plexus Papilloma of the 4th Ventricle and Cerebellopontine Angle in Adult

The choroids plexus papillomas are rare neoplasms of central nervous system, constituting about 0.5% of intracranial tumors. They are most common in children, especially in the first two year of life. In adult, they usually occur within posterior fossa, but cerebellopontine(CP) angle choroids plexus tumor is extremely rare. The authors report two cases of 4th ventricle and CP angle choroids plexus papilloma in adult.

A Case of Oligodendroglioma of the Cerebellar Vermis

In the posterior fossa rarely develops oligodendroglioma and a review of the literature yields reports of two cases in the 4th ventricle in Korea. The authors present a case of 65-year-old woman patient with only the symptoms of increased intracranial pressure such as headache, dizziness and vomiting in spite of a large, irregular calcified mass occupying the cerebellar vermis on the brain CT scan. The caudal portion of the tumor attached firmly to the floor of the 4th ventricle and the complete removal of the mass, associated with a good long-term prognosis, was not feasible.

A Case of Oligodendroglioma in the 4th Ventricle

At least 90% of oligodendroglioma have developed above the tentorium, especially in the frontal lobe, but the case of oligodendroglioma arising in the 4th ventricle of the posterior fossa is extremely rare, 0.08% of the total of intracranial tumors. It was first reported by Van Bogaert in 1928. We experienced a case of 11-year-old male patient admitted by headache, nausea and visual disturbance. The operation was performed after brain CT scan, vertebral angiography and ventriculography. But the patient died on the 66th hospital day due to generalized infection unfortunately. It was histopathologically diagnosed the primary oligodendroglioma of the 4th ventricle after autopsy.

Oligodendroglioma in the Fourth Ventricle: Case Report

The authors present a case of oligodendroglioma in the 4th ventricle which is extremely rare in occurrence. The patient is 11 year-old male whose complaints were severe headache and vomiting. In the brain computes tomogram, hyperdense mass seated in the 4th ventricle with marked hydrocephalus. The patient had operation for removal of the tumor. In the operating field, there are no relation of the choroid plexus and specific vesselas but the tumor attached firmly on the floor of the 4th ventricle. The tumor was removed totally. The pathologic specimens were verified oligodendroglioma.