Changes in multiunit activity pattern in cerebellar cortex associated to olfactory cues during sexual learning in male rats.

The cerebellum is a structure of the central nervous system which has been previously studied with different techniques and animal models and even humans, so it is associated with multiple functions such as cognition, memory, emotional processing, balance, control of movement, among others. Its relationship with sensory systems has already been explored, however, the role it plays in olfactory processing in the cerebellum is unclear. Several hypotheses have been proposed from work done in humans and animal models with neuroimaging and immunohistochemical techniques. Everything seems to indicate that the cerebellar function is of vital importance for the olfactory perception, being able to be controlling not only the olfactory aspect, but also the olfactory processing. In this study we analyzed the multiunit activity in the granular layer of the cerebellar vermis during olfactory stimulation: a session being sexually naive and during four sessions of sexual behavior learning. The amplitude was compared between male naive and sexual experts, as well as between olfactory stimuli. The amplitude of the sexually experienced rats showed the highest values compared to naive ones. Odor of receptive female causes the greatest amplitudes, however, in the control group the amplitude increased when they were sexually experts. The motor, sensory and associative learning generated by the acquisition of sexual experience modifies the activation pattern in the cerebellum by presenting neutral odors or associated with a reward.

Romboencefalosinapsis como causa de ventriculomegalia severa. Reporte de dos casos / Rhomboencephalosynapsis as a cause of severe vetriculomegaly. Report of two cases

We report two cases of a rare pathology of the fetal cerebellum, rhomboencephalosynapsis, a defect characterized by the partial or complete absence of the cerebellar vermis, which is currently associated with severe ventriculomegaly due to defects in the formation of the cerebral aqueduct. These are the first cases reported in Peru

Reportamos dos casos de una patología rara del cerebelo fetal, la romboencefalosinapsis, defecto caracterizado por la ausencia parcial o completa del vermis cerebeloso, frecuentemente asociada a ventriculomegalia severa por defectos en la formación del acueducto de Silvio. Estos constituyen los primeros casos reportados en Perú.

Intracerebellar microinjection of histaminergic compounds on locomotor and exploratory behaviors in mice.

The neural histaminergic system innervates the cerebellum, with a high density of fibers in the vermis and flocculus. The cerebellum participates in motor functions, but the role of the histaminergic system in this function is unclear. In the present study, we investigated the effects of intracerebellar histamine injections and H1, H2 and H3 receptor antagonist injections (chlorpheniramine, ranitidine, and thioperamide, respectively) and H4 receptor agonist (VUF-8430) on locomotor and exploratory behaviors in mice. The cerebellar vermis of male mice was implanted with guide cannula. After three days of recovery,the animals received microinjections of saline or histamine (experiment1), saline or chlorpheniramine (experiment 2), saline or ranitidine(experiment 3), saline or thioperamide (experiment 4), and saline or VUF-8430 (experiment 5) in different concentrations. Five minutes postinjection,the open field test was performed. The data were analyzed using one-way ANOVA and Duncan's post hoc test. The microinjections of histamine, ranitidine or thioperamide did not lead any behavioral effects at the used doses. In contrast, animals that received chlorpheniramine at the highest dose (0.16 nmol) and VUF-8430 at the highest dose (1.48 nmol)were more active in the open field apparatus, with an increase in the number of crossed quadrants, number of rearings and time spent in the central area of the arena, suggesting that chlorpheniramine and VUF-8430 modulates locomotor and exploratory behaviors in mice.

Cerebellar Adrenomedullinergic System. Role in Cardiovascular Regulation.

Adrenomedullin (AM) is a multifunctional peptide which exerts numerous biological activities through the activation of AM1 (CRLR + RAMP2) and AM2 (CRLR + RAMP3) receptors. AM immunoreactivity, AM binding sites and CRLR, RAMP1, RAMP2 and RAMP3 are expressed in rat cerebellar vermis. AM binding sites are discretely and differentially distributed in the rat cerebellar cortex with higher levels detected in SHR when compared with WKY rats. In addition, there is an up-regulation of cerebellar CGRP1 (CRLR + RAMP1) and AM2 (CRLR + RAMP3) receptors and a down-regulation of AM1 (CRLR + RAMP2) receptor during hypertension associated with a decreased AM expression. These changes may constitute a mechanism which contributes to the development of hypertension, and supports the notion that cerebellar AM is involved in the regulation of blood pressure. Cerebellar AM activates ERK, increases cAMP, cGMP and nitric oxide, and decreases antioxidant enzyme activity. These effects are mediated through AM1 receptor since they are blunted by AM(22-52). AM-stimulated cAMP production is mediated through AM2 and CGRP receptors. In vivo administration of AM into the cerebellar vermis caused a profound, specific and dose-dependent hypotensive effect in SHR, but not in normotensive WKY rats. This effect was mediated through AM1 receptor since it was abolished by AM(22-52). In addition, AM injected into the cerebellar vermis reduced vasopressor response to footshock stress. These findings demonstrate dysregulation of cerebellar AM system during hypertension, and suggest that cerebellar AM plays an important role in the regulation of blood pressure. Likewise, they constitute a novel mechanism of blood pressure control which has not been described so far.

Effect of Valsartan on Cerebellar Adrenomedullin System Dysregulation During Hypertension.

Adrenomedullin (AM) and its receptors components, calcitonin-receptor-like receptor (CRLR), and receptor activity-modifying protein (RAMP1, RAMP2, and RAMP3) are expressed in cerebellum. Cerebellar AM, AM binding sites and receptor components are altered during hypertension, suggesting a role for cerebellar AM in blood pressure regulation. Thus, we assessed the effect of valsartan, on AM and its receptor components expression in the cerebellar vermis of Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats. Additionally, we evaluated AM action on superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activity, and thiobarbituric acid reactive substances (TBARS) production in cerebellar vermis. Animals were treated with valsartan or vehicle for 11 days. Rats were sacrificed by decapitation; cerebellar vermis was dissected; and AM, CRLR, RAMP1, RAMP2, and RAMP3 expression was quantified by Western blot analysis. CAT, SOD, and GPx activity was determined spectrophotometrically and blood pressure by non-invasive plethysmography. We demonstrate that AM and RAMP2 expression was lower in cerebellum of SHR rats, while CRLR, RAMP1, and RAMP3 expression was higher than those of WKY rats. AM reduced cerebellar CAT, SOD, GPx activities, and TBARS production in WKY rats, but not in SHR rats. Valsartan reduced blood pressure and reversed the altered expression of AM and its receptors components, as well the loss of AM capacity to reduce antioxidant enzyme activity and TBARS production in SHR rats. These findings demonstrate that valsartan is able to reverse the dysregulation of cerebellar adrenomedullinergic system; and they suggest that altered AM system in the cerebellum could represent the primary abnormality leading to hypertension.

Variante de Dandy Walker: reporte de un caso / Dandy-Walker variant: Case report

Introducción: La variante de Dandy Walker se define como una hipoplasia variable del vermis cerebeloso, con o sin aumento de la fosa posterior y sin elevación del tentorio. Objetivo: Describir el caso de una enfermedad poco frecuente y hacer énfasis en la necesidad de precisar la etiología de malformaciones prenatales en niños que son clasificados erróneamente como parálisis cerebral secundaria a asfixia, así como su manejo multidisciplinario. Caso clínico: Paciente varón, de 8 años de edad, con antecedentes de parálisis cerebral infantil, epilepsia y retraso del desarrollo, que fue ingresado por historia de convulsiones tónico-clónicas. Durante su hospitalización presentó múltiples episodios convulsivos, controlados con anticonvulsivantes. Se realizó tomografía computarizada, observándose comunicación entre la cisterna magna y el cuarto ventrículo; este último aumentado de tamaño. Además, el vermis del cerebelo presentaba hipoplasia parcial, siendo estos hallazgos compatibles con una variante del síndrome Dandy Walker. Conclusión: La variante de Dandy Walker puede ser sintomática o asintomática, y las imágenes encontradas no necesariamente se relacionan con las alteraciones del desarrollo, debido a los múltiples síndromes y alteraciones cromosómicas vinculadas a este cuadro. La presentación clínica y el pronóstico dependen de las alteraciones presentes. Por ello, es importante un manejo multidisciplinario considerando que el tratamiento depende de los síntomas presentados.

Introduction: Dandy Walker variant is defined by a variable hypoplasia of the cerebellar vermix with or without posterior fossa increase and without tentorium elevation. Objective: describe the case of a rare disease and emphasise the need to clarify the aetiology of prenatal malformations, as well as its multidisciplinary management. Case report: A male patient, 8 years of age, with a history of Infantile Cerebral Palsy and epilepsy, who was admitted with a history of tonic-clonic seizures. He was admitted due to psycho-motor developmental delay. During his hospitalisation, he had multiple seizure episodes, controlled with anticonvulsants. A computerized tomography was performed, in which communication was observed between the cisterna magna and fourth ventricle (the latter increased in size). In addition, the cerebellar vermix showed a partial hypoplasia. All these findings were compatible with a variant of the Dandy Walker syndrome. Conclusion: Dandy Walker variant may be asymptomatic and the images found may not indicate them as the cause of developmental disorders, due to its association with multiple syndromes and chromosomal abnormalities. Clinical presentation and prognosis depends on the related disorders, and a multidisciplinary approach is important, because the treatment depends on the symptoms presented.

Efecto de la adrenomedulina cerebelosa frente al estrés agudo / Effect of cerebellar adrenomedullin during acute stress

La adrenomedulina (AM) es un péptido involucrado en la regulación cardiovascular. En el cerebelo, la densidad de los receptores de la AM se encuentra alterada durante la hipertensión, sugiriendo un posible papel del sistema adrenomedulinérgico cerebelar en la regulación de la presión arterial (PA). El objetivo del presente estudio fue evaluar el efecto funcional in vivo de la AM durante el estrés agudo, mediante la administración in situ de AM en el vermis cerebelar de la rata. Se emplearon ratas adultas normotensas Wistar Kyoto (WKY) y Sprague Dawley (SD) y ratas espontáneamente hipertensas (SHR) las cuales fueron anestesiadas y posteriormente canuladas en el vermis cerebelar. El estrés se indujo mediante el uso del estímulo eléctrico plantar (EEP). Los animales fueron divididos en grupos que recibieron AM (0,2 o 200 pmol/5μL) o vehículo (solución fisiológica, 5μL). La PA se determinó antes del experimento y después de la administración del tratamiento respectivo, seguida de la aplicación del EEP (100 V, 5 Hz, 10 mseg, durante 4 minutos). La PA se determinó mediante pletismografía digital no invasiva. Los resultados demuestran que la microinyección de AM (0,2 y 200 pmol) in situ en el vermis cerebeloso en ratas SD, WKY y SHR disminuye significativamente la respuesta presora frente al estrés inducido por el EEP, lo que sugiere que la acción hipotensora está mediada a través de la regulación del eflujo simpático. Estos hallazgos demuestran la participación de la AM cerebelosa en la regulación de la respuesta cardiovascu lar frente al estrés.

Adrenomedullin (AM) is a peptide involved in cardiovascular regulation. In the cerebellum, the density of AM receptors is altered during hypertension, suggesting a pos sible role of cerebellar adrenomedulinergic system in the regulation of blood pressure (BP). The aim of this study was to evaluate the functional role of AM during acute stress, by in situ administration of AM into the cerebellar vermis in rats. Adult normotensive Wistar Kyoto (WKY) and Sprague Dawley (SD) rats and spontaneously hypertensive rats (SHR), were anes thetized and their cerebellar vermis cannulated. Footshock was used as stressor. Animals were divided into groups that received either AM (0.2 and 200 pmol/5μL) or vehicle (physiological saline, 5μL). The BP was determined, using noninvasive digital plethysmography, before and after treatment, followed by footshock (100V, 5 Hz, 10 msec, for 4 minutes). The results show that microinjection of AM (0.2 and 200 pmol) in situ into the cerebellar vermis in SD, WKY and SHR rats, significantly decreased the pressor response induced by footshock stress, sugges ting that the hypotensive action is mediated through regulation of sympathetic outflow. Taken together, our results demonstrate a role of cerebellar AM in the regulation of cardiovascular response to stress.

Síndrome cerebeloso por mesalamina: reporte de un caso / Cerebellar syndrome for mesalamine: a case report

El cerebelo proviene del latín "pequeño cerebro", es aproximadamente una décima parte del cerebro en tamaño y peso, se encuentra en la fosa craneal posterior. está conectado directamente o indirectamente a una variedad de estructuras, incluyendo el tronco cerebral, la columna vertebral, las regiones corticales y subcorticales. El cerebelo contiene casi el 80 % del total de las neuronas del cerebro y se compone de formas diferenciadas de unidades neuronales, cada una compartiendo microcircuitos cerebelosos básicos. El cerebelo está formado por dos hemisferios laterales y una porción media o vermis . El cerebelo tiene varias funciones: coordinar los movimientos voluntarios especializados al influir en la actividad muscular y controlar el equilibrio, el tono muscular a través de conexiones con el sistema vestibular, la médula espinal y sus neuronas motoras alfa. Dentro de la corteza del cerebelo existe una organización somatotópica de las partes del cuerpo. El cerebelo es una pieza clave para el procesamiento de la información y participa en numerosas actividades motoras y no motoras, gracias a las características anatómicas de sus circuitos, las enormes capacidades de análisis y la alta conectividad con otras áreas del cerebro, puede verse afectado por diferentes factores como: anormalidades en el desarrollo embrionario, tóxicos, enfermedades autoinmunes, inflamatorias, vasculares y metabólicas, infecciones, tumores primarios y secundarios, traumas, iatrogénicos, enfermedades genéticas, esporádicas, dando origen a signos y síntomas que causan un síndrome cerebeloso de acuerdo al área anatómica comprometida. En la literatura científica no hay reportes de casos de síndrome cerebeloso por mesalamina (mesalazina). A continuación presentamos el primer caso.

Cerebellum is Latin for "little brain" is about a tenth of the brain in size and weight, is in the posterior cranial fossa. It connects directly or indirectly to a variety of structures, including brainstem, spinal cord, cortical and subcortical regions. The cerebellum contains almost 80% of all neurons in the brain and consists of different forms of neuronal units, each sharing basic cerebellar microcircuits. The cerebellum is formed by two lateral hemispheres and vermis or a middle portion . The cerebellum has several functions: coordinate movements specialized volunteers to influence muscle activity and control the balance, muscle tone through connections with the vestibular system, the spinal cord and alpha motor neurons. Within the cerebellar cortex somatotopic organization exists a body part. The cerebellum is a key to information processing and participates in numerous motor and non-motor activities, thanks to the anatomical characteristics of its routes, huge analysis capabilities and high connectivity with other brain areas, can be affected by different factors such as abnormalities in embryonic development, toxic, autoimmune, inflammatory, vascular and metabolic, infections, primary and secondary tumors, trauma, iatrogenic, genetic diseases, sporadic, giving rise to signs and symptoms that cause cerebellar syndrome according to compromised anatomical area. In the scientific literature no reported cases of cerebellar syndrome mesalamina (mesalazina), we report the first case.

[Dandy-Walker variant: Case report]. / Variante de Dandy Walker: reporte de un caso.

INTRODUCTION: Dandy Walker variant is defined by a variable hypoplasia of the cerebellar vermix with or without posterior fossa increase and without tentorium elevation. OBJECTIVE: describe the case of a rare disease and emphasise the need to clarify the aetiology of prenatal malformations, as well as its multidisciplinary management. CASE REPORT: A male patient, 8 years of age, with a history of Infantile Cerebral Palsy and epilepsy, who was admitted with a history of tonic-clonic seizures. He was admitted due to psycho-motor developmental delay. During his hospitalisation, he had multiple seizure episodes, controlled with anticonvulsants. A computerized tomography was performed, in which communication was observed between the cisterna magna and fourth ventricle (the latter increased in size). In addition, the cerebellar vermix showed a partial hypoplasia. All these findings were compatible with a variant of the Dandy Walker syndrome. CONCLUSION: Dandy Walker variant may be asymptomatic and the images found may not indicate them as the cause of developmental disorders, due to its association with multiple syndromes and chromosomal abnormalities. Clinical presentation and prognosis depends on the related disorders, and a multidisciplinary approach is important, because the treatment depends on the symptoms presented.

Congenital Cerebellar Vermis Aplasia Associated with Hydrocephalus in a Foal

A 2-day-old Mangalarga Marchador colt was presented with clinical signs of severe mental depression, unable to stand, and lacking a suckling reflex. Despite intensive medical care, there was no improvement and the colt died 30 hours later. Gross lesions were characterized by aplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle, communicant hydrocephalus involving all ventricles and villous hyperplasia of the choroid plexus in the fourth ventricle. The cerebral parenchyma adjacent to lateral ventricles was markedly reduced. In addition, there was aspiration pneumonia. Aplasia of the cerebellar vermis and cystic dilatation of the fourth ventricle could be compared to the Dandy-Walker-syndrome (DWS). Nevertheless, congenital cerebellar anomalies combined with villous hyperplasia of the choroid plexus in the fourth ventricle and hydrocephalus are describing for the first time in animals, alerting clinicians and pathologists for future investigations about the incidence and etiology of the condition.

Congenital Cerebellar Vermis Aplasia Associated with Hydrocephalus in a Foal

A 2-day-old Mangalarga Marchador colt was presented with clinical signs of severe mental depression, unable to stand, and lacking a suckling reflex. Despite intensive medical care, there was no improvement and the colt died 30 hours later. Gross lesions were characterized by aplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle, communicant hydrocephalus involving all ventricles and villous hyperplasia of the choroid plexus in the fourth ventricle. The cerebral parenchyma adjacent to lateral ventricles was markedly reduced. In addition, there was aspiration pneumonia. Aplasia of the cerebellar vermis and cystic dilatation of the fourth ventricle could be compared to the Dandy-Walker-syndrome (DWS). Nevertheless, congenital cerebellar anomalies combined with villous hyperplasia of the choroid plexus in the fourth ventricle and hydrocephalus are describing for the first time in animals, alerting clinicians and pathologists for future investigations about the incidence and etiology of the condition.(AU)

Estudio neuropsicológico pre y posquirúrgico en dos niños de 8 años de edad con tumor en fosa posterior / Neuropsychological study pre and post surgical in two children aged 8 years with posterior fossa tumor

Objetivo: Identificar y describir las diferencias neuropsicológicas antes y después de resecar el tumor en 2 pacientes de 8 años de edad con una neoplasia en la fosa posterior. Metodología: Se realizó evaluación neuropsicológica pre y posquirúrgica a 2 pacientes de 8 años de edad del Instituto Nacional de Pediatría, uno femenino con quiste aracnoideo en cisterna paravermiana y otro masculino con meduloblastoma en vermis y se compararon los datos obtenidos antes de extirpación de tumor y después de ella. Para la obtención del IQ se aplicó el WISC-IV y para las otras funciones, la Evaluación Neuropsicológica Infantil (ENI), para niños de 5 a 16 años, obteniéndose sus valores en percentiles que se igualaron con la clasificación cualitativa. Resultados: Los 2 pacientes presentaron deficiencias en el IQ, en Funciones Cognitivas, en las Habilidades de Rendimiento Académico, así como en sus Funciones Ejecutivas. A pesar de que no se aplicó quimioterapia ni radioterapia, tanto antes de la cirugía, como después de la extirpación del tumor, empeorando dichas funciones después de la extirpación. Conclusiones: Los tumores en Fosa Posterior originan diversas alteraciones neuropsicológicas similares a las observadas con lesiones en la corteza cerebral, dichas alteraciones se hacen más severas después de la extirpación del tumor; esta evolución puede presentar un dilema a la luz de la Bioética: ¿Se prolonga la vida a expensas de mayor deterioro neurocognitivo al quitar el tumor, o no se opera para evitar mayor deterioro en la calidad de vida y se reduce el tiempo de vida?.

Aim: Identify and describe the neuropsychological differences before and after surgery in 2 patients 8 years of age with a tumor in the posterior fossa. Methodology: Neuropsychological assessment was performed before and after surgery to 2 patients (8 years of age), one female with arachnoid cyst in paravermian cyst and another male with medulloblastoma in vermis and we compared the data obtained before removal of tumor and after. We use the following Neuropsychological Tests: WISC-IV was applied to assess IQ and Child Neuropsychological Assessment (ENI) was to evaluate cognitive functions. Results: The 2 patients had deficits in IQ, cognitive functions, the academic performance skills and his executive skills, even without chemotherapy or radiotherapy, both before surgery and after removal of the tumor. These functions worsened after surgery. Conclusions: Posterior fossa tumors originate many various neuropsychological similar to those observed in cerebral cortex, these changes are most evident after removal of the tumor, this evolution can present a dilemma in light of Bioethics: Is justified to prolong the life at expense of neurocognitive impairment, after removing a big tumor, or not to operate preventing further deterioration in the quality of life and reducing the lifetime?.

Effect of histamine H1 and H2 receptor antagonists, microinjected into cerebellar vermis, on emotional memory consolidation in mice

This study investigated the effects of histamine H1 or H2 receptor antagonists on emotional memory consolidation in mice submitted to the elevated plus maze (EPM). The cerebellar vermis of male mice (Swiss albino) was implanted using a cannula guide. Three days after recovery, behavioral tests were performed in the EPM on 2 consecutive days (T1 and T2). Immediately after exposure to the EPM (T1), animals received a microinjection of saline (SAL) or the H1 antagonist chlorpheniramine (CPA; 0.016, 0.052, or 0.16 nmol/0.1 µL) in Experiment 1, and SAL or the H2 antagonist ranitidine (RA; 0.57, 2.85, or 5.7 nmol/0.1 µL) in Experiment 2. Twenty-four hours later, mice were reexposed to the EPM (T2) under the same experimental conditions but they did not receive any injection. Data were analyzed using one-way ANOVA and the Duncan test. In Experiment 1, mice microinjected with SAL and with CPA entered the open arms less often (%OAE) and spent less time in the open arms (%OAT) in T2, and there was no difference among groups. The results of Experiment 2 demonstrated that the values of %OAE and %OAT in T2 were lower compared to T1 for the groups that were microinjected with SAL and 2.85 nmol/0.1 µL RA. However, when animals were microinjected with 5.7 nmol/0.1 µL RA, they did not show a reduction in %OAE and %OAT. These results demonstrate that CPA did not affect behavior at the doses used in this study, while 5.7 nmol/0.1 µL RA induced impairment of memory consolidation in the EPM.

Cerebellar vermis: topography and variations / Vermis cerebelar: topografía y variaciones

The vermis is described as the unpaired, median portion of the cerebellum to which the hemispheres are attached. Both the vermis and the hemispheres are formed by folia that, grouped together, are called lobules. The material analyzed consisted of a sample made up of 43 adult male cerebella fixed in 10 percent formaldehyde and sliced medially. The lingula was attached to the superior medullary velum in 100 percent (43) of the cerebella, varying only in size. In 80 percent (32) of the cerebella, the central lobe contained one folium; 7.5 percent (3) had two folia with the first larger than the second; 10 percent (4) had two folia with the second larger than the first; and 2.5 percent (1) had two folia of equal size. In 5 percent (2) of the cerebella, the folium of the vermis emerged from the declive; in 47.5 percent (19), the folium emerged from the central white matter; and in 42.5 percent (17), the folium emerged from the tuber. There was no variation in the lobules, culmen, pyramid, uvula or nodule in the sample studied. Contrary to what many believe, the folia of the cerebellum exhibit variations in form, number and arrangement. However, these variations are virtually unreported, which often hinders the determination of the limits of these structures by students of anatomy of the cerebellum.

El vermis se describe como la parte impar, mediana del cerebelo por la que los hemisferios están conectados. Tanto el vermis como los hemisferios están formados por folium que, de forma conjunta, se llaman lóbulos. El material analizado consistió en una muestra compuesta por 43 cerebelos de hombres, adultos, fijados en formol al 10 por ciento y cortados en rodajas en sentido medial. La língula se adjuntó al velo medular superior en 100 por ciento (43) del cerebelo, y sólo varían en tamaño. En el 80 por ciento (32) del cerebelo, el lóbulo central contenía un folium, 7,5 por ciento (3) había dos folium con el primero más grande que el segundo, 10 por ciento (4) tuvo dos folium con el segundo más grande que el primero, y 2,5 por ciento (1) tenía dos folium de igual tamaño. En el 5 por ciento (2) de los cerebelos, el folium del vermis surgido del declive, en el 47,5 por ciento (19), el folium surgido de la sustancia blanca central, y en el 42,5 por ciento (17), el folium surgido del tubérculo. No hubo, en la muestra estudiada, variación en los lóbulos, culmen, pirámide, úvula o nódulo. Contrariamente a lo que muchos creen, el folium del cerebelo presentan variaciones en la forma, número y disposición. Sin embargo, estas variaciones son virtualmente inadvertidas, lo que a menudo dificulta la determinación de los límites de estas estructuras del cerebelo, por los estudiantes de la anatomía.