Direct contribution of the sensory cortex to the judgment of stimulus duration.

Decision making frequently depends on monitoring the duration of sensory events. To determine whether, and how, the perception of elapsed time derives from the neuronal representation of the stimulus itself, we recorded and optogenetically modulated vibrissal somatosensory cortical activity as male rats judged vibration duration. Perceived duration was dilated by optogenetic excitation. A second set of rats judged vibration intensity; here, optogenetic excitation amplified the intensity percept, demonstrating sensory cortex to be the common gateway both to time and to stimulus feature processing. A model beginning with the membrane currents evoked by vibrissal and optogenetic drive and culminating in the representation of perceived time successfully replicated rats' choices. Time perception is thus as deeply intermeshed within the sensory processing pathway as is the sense of touch itself, suggesting that the experience of time may be further investigated with the toolbox of sensory coding.

Síndrome de Herlyn-Werner-Wünderlich: a propósito de un caso / Herlyn-Werner-Wiinderlich syndrome: a case report

A pesar de que la asociación entre útero didelfo, hemivagina obstruida y agenesia renal homolateral (síndrome de Herlyn-Werner-Wünderlich) ha sido reportada en la literatura ginecológica, no es familiar al especialista en diagnóstico por imágenes, en tanto no actúa en el campo ginecoobstétrico. Si bien infrecuente, hasta el año 2006 han sido reportados aproximadamente 200 casos en la literatura mundial.

Even though the association of uterus didelphys with obstructed hemivagina and ipsilateral renal agenesis (Herlyn-Werner-Wiinderlich syndrome) has been reported in the gynecologic literature, it is not familiar to radiologists not specialized in the field of obstetrics and gynecology. Though rare, until 2006 this syndrome has been reported in approximately 200 cases in worldwide literature.

Tumor pseudopapilar sólido del páncreas: reporte de dos casos y revisión de la literatura / Solid pseudopapillary tumor of the pancreas: report of two cases and literature review

El Tumor Sólido Pseudopapilar del Páncreas (TSPP) constituye una neoplasia infrecuente que se observa generalmente en mujeres jóvenes y que se caracteriza por presentarse como una masa sólida bien definida comúnmente asociada a hemorragia intratumoral. Sin embargo, este tumor puede demostrar un patrón de presentación atípico con metástasis a distancia, obstrucción ductal, invasión parenquimatosa y extracapsular o presentarse en pacientes de sexo masculino. En la actualidad, esta infrecuente lesión puede ser adecuadamente identificada y caracterizada en la mayoría de los casos con los modernos métodos diagnósticos disponibles. El propósito de este trabajo es presentar dos casos de tumor sólido pseudo papilar de páncreas (uno de presentación mixta y otro de presentación quística), realizando simultáneamente una revisión bibliográfica de esta entidad.

The solid pseudopapillary tumor of the pancreas is a rare neoplasm usually found in young women. The typical solid pseudopapillary tumor is characterized by a well-encapsulated mass generally associated with intratumoral hemorrhage. However, this tumor may have an atypical appearance, such as metastasis, ductal obstruction, parenchymal and extracapsular invasion. It may mimic an islet cell tumor, present intratumoral calcification, or occur in male patients. Both typical and atypical manifestations of solid pseudopapillary tumor can be seen with cross-sectional imaging. The purpose of this report is to present two cases of solid pseudopapillary tumor of the pancreas, and to make a brief literature review.

Mesenterio Nebuloso: hallazgos por Tomografía Computada / Misty Mesentery: computed tomography findings

La alteración en la densidad del tejido adiposo mesentérico constituye frecuentemente el hallazgo principal que permite sospechar la existencia de una enfermedad mesentérica o intestinal. El término "Mesenterio Nebuloso" hace referencia a la apariencia tomográfica del mesenterio cuando el mismo es afectado por células inflamatorias, líquido (edema, linfa y/o sangre), tumor o fibrosis.

An alteration in the density of the mesenteric fat is often the principal clue of underlying mesenteric and bowel disease. The Term "Misty Mesentery" describes the Computed Tomographic appearance of mesenteric fat infiltrated by inflammatory cells, fluid (edema, lymph, and/or blood), tumor, and fibrosis.

Feocromocitoma quístico: a propósito de un caso / Cystic pheochromocytoma: report of a case

La prevalencia de los feocromocitomas en autopsia es de aproximadamente 0.13%. Estas neoplasias, compuestas de células cromafínicas derivadas embiológicamente del neuroectodermo son responsables de tan solo el 0.1% al 0.3% de los casos de hipertensión arterial. Los feocromocitomas constituyen lesiones hipervascularizadas, las que suelen presentar degeneración quística parcial o focal. Sin embargo, y de manera infrecuente, pueden sufrir degeneración quística total o subtotal existiendo algunos reportes en la literatura mundial que describen tumores totalmente quísticos. Se ha postulado que dicha degeneración quística sería secundaria a hemorragia intraparenquimatosa seguida de necrosis y posterior resorción, reflejando estas lesiones un proceso de necrosis y liquefacción intratumoral.

Prevalence of pheochromocytomas at autopsy is 0.13% and these uncommon neoplasms account for only 0.1%-0.3% of cases of hypertension. The tumor is composed of chromaffin cells, wich are embryologically derived from the neuroectoderm. Pheochromocytomas are quite vascular lesions. However, they frequently manifest with focal or partial cystic degeneration. Total o subtotal cystic degeneration is not common. There have been several reports in the literature describingtotally cystic tumors. It has been postulated that this cystic degeneration starts with intraparenchymal hemorrhage followed by necrosis; the areas of necrosis later undergo resorption. The cystic components of pheochromocytomas reflect this necrosis and liquefaction within the tumor.

Electromyographic evaluation of anterior temporal and suprahyoid muscles using habitual methods to determine clinical rest position.

The purpose of this study was to compare the electromyographic (EMG) activity of the anterior temporal and suprahyoid muscles using habitual methods to determine the clinical rest position. The sample included 26 healthy subjects with natural dentition, bilateral molar support, and bilateral molar Angle Class I occlusion. Bipolar surface electrodes were located on the right anterior temporal and suprahyoid muscles for EMG recordings. In each subject EMG activity was recorded while standing while performing the following jaw posture tasks: during light occlusal contact in the intercuspal position; during and after pronouncing the word Mississippi, during and after pronouncing the Spanish terms Sesenta y seis (English translation: sixty six); during and after pronouncing the word, business, during and after swallowing of saliva; and while maintaining their mandible in a relaxed posture. Anterior temporal EMG activity in the intercuspal position was significantly higher than all the other conditions. The same was observed in the suprahyoid muscles excepting after pronouncing the words Mississippi, and business. EMG activity recorded in the clinical rest position by means of phonetic methods, swallowing of saliva and maintaining the mandible in a relaxed posture did not show a significant difference. From an EMG point of view any of these methods could be used to determine clinical rest position.

Laterotrusive occlusal schemes and jaw posture tasks effects on supra- and infrahyoid EMG activity in the lateral decubitus position.

The purpose of this study was to determine the effect of canine guidance and group function on supra- and infrahyoid EMG activity in the lateral decubitus position at different jaw posture tasks. The sample included 40 healthy subjects with natural dentition and bilateral molar support, 20 with bilateral canine guidance and 20 with bilateral group function. An inclusion criterion was that subjects had to be free of signs and symptoms of any dysfunction of the masticatory system. Bipolar surface electrodes were located on the left supra- and infrahyoid muscles for EMG recordings. In the lateral decubitus position, EMG activity was recorded in subjects with canine guidance or group function, during the following jaw posture tasks: A. maximal clenching in the edge-to edge lateral contact position; B. grinding from intercuspal position to edge-to-edge lateral contact position, and C. grinding from edge-to-edge lateral contact position to intercuspal position. Supra- and infrahyoid EMG activity was not significantly different with canine guidance or group function (mixed model with unstructured covariance matrix). Overall comparison of suprahyoid or infrahyoid EMG activity among the three jaw posture tasks studied showed a significantly higher activity during jaw posture task A (clenching) than jaw posture tasks B and C (grinding). Suprahyoid EMG activity was significantly higher during jaw posture task C than B, whereas infrahyoid EMG activity did not present a significant difference between jaw posture tasks C and B. These EMG patterns observed could be of clinical importance in the presence of parafunctional habits, i.e., clenching and/or grinding. The neurophysiological mechanisms involved are discussed.

Síndrome del Nevus Azul (Síndrome de Bean) / Blue Nevus Syndrome (Bean Syndrome)

El Síndrome del Nevus Azul (SNA) es una cantidad infrecuente caracterizada por la presencia de malformaciones vasculares cutáneas y gastrointestinales múltiples que generalmente producen hemorragia gastrointestinal masiva u oculta asociada a deficiencia de hierro secundario a sangrado. Nosotros describimos un paciente de 7 años de edad de sexo masculino que presentaba episodios recurrentes de anemia crónica asociada a múltiples malformaciones venosas.

Does head posture have a significant effect on the hyoid bone position and sternocleidomastoid electromyographic activity in young adults?

The aim of this study was to evaluate the associations between head posture (head extension, normal head posture, and head flexion) and anteroposterior head position, hyoid bone position, and the sternocleidomastoid integrated electromyographic (IEMG) activity in a sample of young adults. The study included 50 individuals with natural dentition and bilateral molar support. A lateral craniocervical radiograph was taken for each subject and a cephalometric analysis was performed. Head posture was measured by means of the craniovertebral angle formed by the MacGregor plane and the odontoid plane. According to the value of this angle, the sample was divided into the following three groups: head extension (less than 95 degrees); normal head posture (between 95 degrees and 106 degrees); and head flexion (more than 106 degrees). The following cephalometric measurements were taken to compare the three groups: anteroposterior head position (true vertical plane/pterygoid distance), anteroposterior hyoid bone position (true vertical plane-Ha distance), vertical hyoid bone position (H-H' distance in the hyoid triangle), and CO-C2 distance. In the three groups, IEMG recordings at rest and during swallowing of saliva and maximal voluntary clenching were performed by placing bipolar surface electrodes on the right and left sternocleidomastoid muscles. In addition, the condition with/without craniomandibular dysfunction (CMD) in each group was also assessed. Head posture showed no significant association with anteroposterior head position, anteroposterior hyoid bone position, vertical hyoid bone position, or sternocleidomastoid IEMG activity. There was no association to head posture with/without the condition of CMD. Clinical relevance of the results is discussed.