Factors Affecting Frequency Discrimination of Vibrotactile Stimuli: Implications for Cortical Encoding

BACKGROUND: Measuring perceptual judgments about stimuli while manipulating their physical characteristics can uncover the neural algorithms underlying sensory processing. We carried out psychophysical experiments to examine how humans discriminate vibrotactile stimuli. METHODOLOGY/PRINCIPAL FINDINGS: Subjects compared the frequencies of two sinusoidal vibrations applied sequentially to one fingertip. Performance was reduced when (1) the root mean square velocity (or energy) of the vibrations was equated by adjusting their amplitudes, and (2) the vibrations were noisy (their temporal structure was irregular). These effects were super-additive when subjects compared noisy vibrations that had equal velocity, indicating that frequency judgments became more dependent on the vibrations' temporal structure when differential information about velocity was eliminated. To investigate which areas of the somatosensory system use information about velocity and temporal structure, we required subjects to compare vibrations applied sequentially to opposite hands. This paradigm exploits the fact that tactile input to neurons at early levels (e.g., the primary somatosensory cortex, SI) is largely confined to the contralateral side of the body, so these neurons are less able to contribute to vibration comparisons between hands. The subjects' performance was still sensitive to differences in vibration velocity, but became less sensitive to noise. CONCLUSIONS/SIGNIFICANCE: We conclude that vibration frequency is represented in different ways by different mechanisms distributed across multiple cortical regions. Which mechanisms support the “readout” of frequency varies according to the information present in the vibration. Overall, the present findings are consistent with a model in which information about vibration velocity is coded in regions beyond SI. While adaptive processes within SI also contribute to the representation of frequency, this adaptation is influenced by the temporal regularity of the vibration

Activation of the Innate Immune Response against DENV in Normal Non-Transformed Human Fibroblasts

In this work, we demonstrate that that both human whole skin and freshly isolated skin fibroblasts are productively infected with Dengue virus (DENV). In addition, primary skin fibroblast cultures were established and subsequently infected with DENV-2; we showed in these cells the presence of the viral antigen NS3, and we found productive viral infection by a conventional plaque assay. Of note, the infectivity rate was almost the same in all the primary cultures analyzed from different donors. The skin fibroblasts infected with DENV-2 underwent signaling through both TLR3 and RIG-1, but not Mda5, triggering up-regulation of IFNβ, TNFα, defensin 5 (HB5) and β defensin 2 (HβD2). In addition, DENV infected fibroblasts showed increased nuclear translocation of interferon (IFN) regulatory factor 3 (IRF3), but not interferon regulatory factor 7 IRF7, when compared with mock-infected fibroblasts. Our data suggest that fibroblasts might even participate producing mediators involved in innate immunity that activate and contribute to the orchestration of the local innate responses. This work is the first evaluating primary skin fibroblast cultures obtained from different humans, assessing both their susceptibility to DENV infection as well as their ability to produce molecules crucial for innate immunity

Características demográficas, estado nutricional, hábitos alimentarios y de actividad física, infección por Helicobacter pylori y parasitosis intestinal en niños de preescolares municipales en Cuenca, Ecuador

Ecuador es un país en transición nutricional. Datos nacionales indican que la prevalencia de sobrepeso/obesidad se triplica desde la edad preescolar a la edad escolar, mientras que el retraso del crecimiento sigue siendo prevalente. Se realizó un estudio transversal en centros infantiles municipales en Cuenca, Ecuador, para identificar factores que contribuyen a la transición nutricional. De los 97 niños participantes, 5.3% tenían sobrepeso/obesidad y el 8.5% tenían retraso del crecimiento. A pesar de que no hubo casos de niños con bajo peso, el 19.0% de los padres/cuidadores consideraba que su hijo tenía bajo peso. La mayoría de las familias tenían algún grado de inseguridad alimentaria (71.4%). Los padres informaron que la mayoría de los niños bebía agua, con una frecuencia diaria, en el hogar (70.5%), mientras que los profesores señalaron que menos de la mitad consume agua en el centro infantil (41.5%). Los padres y profesores informaron que el 89.5% y el 34.7% de los niños consumían verduras MASKANA, Vol. 9, No. 1, 2018 Revista semestral de la DIUC 42 https://doi.org/10.18537/mskn.09.01.05 diariamente, y el 70.5% y el 57.9% consumían fruta diariamente en casa y en la escuela, respectivamente. Alrededor de 75% de los padres/cuidadores y profesores informaron que los niños dedicaban ≥1 hora diaria de actividad física en la casa y en el centro infantil. La mitad de los padres informaron que los niños pasaban por lo menos 2 horas diarias frente a la televisión, tableta o computador. En el examen de heces se encontró que el 26.1% resultó positivo para el antígeno de Helicobacter pylori y el 19.3% para parásitos intestinales. Este estudio proporciona información sobre áreas potenciales para promover salud y educación en esta población, como por ejemplo hábitos de alimentación y actividad física. Sin embargo, se deberían considerar factores de riesgo relacionados con la pobreza que afectan la salud, como la inseguridad alimentaria y una alta prevalencia de infección por Helicobacter pylori y parasitosis intestinal.Ecuador is a country in nutritional transition. National data show that the prevalence of overweight and obesity more than triples from the preschool to school-aged years, while stunting remains prevalent. A cross-sectional study in the municipal preschools in Cuenca was conducted to better understand the contributing factors to this nutritional transition. Of the 97 children in the sample population, 5.3% were overweight or obese and 8.5% were stunted. Despite no underweight children, 19.0% of the parents or caregivers considered their child to be underweight. Most households had some degree of food insecurity (71.4%). Parents reported that most children drank water daily at home (70.5%), but according to the teachers, less than half drank water at school daily (41.5%). Parents and teachers, respectively, reported that 89.5% and 34.7% of the children consumed vegetables daily and 70.5% and 57.9% consumed fruit daily at home or school. About three-quarters of the parents and teachers reported that children dedicated ≥1 hour daily to physical activity, at home and school. Half of the parents reported that their child spent at least 2 hours per day watching the television, using an electronic tablet or computer. Stool examination showed that 26.1% of children were positive for Helicobacter pylori antigen and 19.3% for intestinal parasites. This study provided insight into potential areas to focus health education and promotion among this population, for example, in diet and physical activity habits. However, other important factors including poverty related risk factors, such as household food insecurity, and high prevalence of Helicobacter pylori infection and intestinal parasitosis, should be considered simultaneously in such efforts

The effect of albendazole treatment on non-seizure outcomes in patients with symptomatic neurocysticercosis

Antecedentes: existe poca información sobre el impacto del tratamiento antihelmíntico en los síntomas clínicos distintos de las convulsiones en la neurocisticercosis (NC). Investigamos el efecto del albendazol en los síntomas no convulsivos experimentados por pacientes con NC. Métodos: Los datos provienen de un ensayo controlado aleatorio que compara albendazol más prednisona con placebo más prednisona para el tratamiento de NC entre 173 pacientes.con quistes de NC activos o de transición y síntomas de nueva aparición. Realizamos una regresión binomial negativa para examinar el número de visitas de seguimiento cuando se notificó un síntoma, regresión logística para examinar la probabilidad de experimentar el síntoma y modelos de riesgos proporcionales de Cox para examinar el tiempo hasta la primera notificación del síntoma. Resultados: El ochenta y cinco por ciento de los pacientes informaron al menos un síntoma sin convulsiones al inicio del estudio. Aquellos tratados con albendazol tuvieron probabilidades significativamente más bajas de pérdida de memoria y / o confusión durante los meses 1-24 (odds ratio [OR] 0.42, p = 0.037) y significativamente mayores probabilidades de ansiedad y / o depresión durante los meses 1-12 (OR 1.87 , p = 0,049). No hubo diferencia en el tratamiento al experimentar síntomasen general o al experimentar dolores de cabeza, debilidad de las extremidades o trastornos de la marcha, vómitos, náuseas y / o dolor de estómago o trastornos visuales durante el período de seguimiento. Conclusiones: Si bien la prevalencia de los síntomas sin crisis fue alta, el tratamiento con albendazol se asoció con solo dos diferencias significativas en los síntomas sin crisis durante el seguimiento. Se necesita más investigación para identificar estrategias para reducir la carga de síntomas a largo plazo en pacientes conBackground Randomized controlled trials have found an inconsistent effect of anthelmintic treatment on long-term seizure outcomes in neurocysticercosis. The objective of this study was to further explore the effect of albendazole treatment on long-term seizure outcomes and to determine if there is evidence for a differential effect by seizure type. Methods In this trial, 178 patients with active or transitional neurocysticercosis cysts and new-onset symptoms were randomized to 8 days of treatment with albendazole (n= 88) or placebo (n= 90), both with prednisone, and followed for 24 months. We used negative binomial regression and logistic regression models to determine the effect of albendazole on the number of seizures and probability of recurrent or new-onset seizures, respectively, over follow-up. Results Treatment with albendazole was associated with a reduction in the 

Validity of a PCR assay in CSF for the diagnosis of neurocysticercosis

Objective: To prospectively evaluate the validity of a PCR assay in CSF for the diagnosis of neurocysticercosis (NC). Methods: We conducted a multicenter, prospective case-control study, recruiting participants from 5 hospitals in Cuenca, Ecuador, from January 2015 to February 2016. Cases fulfilled validated diagnostic criteria for NC. For each case, a neurosurgical patient who did not fulfill the diagnostic criteria for NC was selected as a control. CT and MRI, as well as a CSF sample, were collected from both cases and controls. The diagnostic criteria to identify cases were used as a reference standard. Results: Overall, 36 case and 36 control participants were enrolled. PCR had a sensitivity of 72.2% (95% confidence interval [CI] 54.8%–85.8%) and a specificity of 100.0% (95% CI 90.3%–100.0%). For parenchymal NC, PCR had a sensitivity of 42.9% (95% CI 17.7%–71.1%), and for extraparenchymal NC, PCR had a sensitivity of 90.9% (95% CI 70.8%–98.9%). Conclusions: This study demonstrated the usefulness of this PCR assay in CSF for the diagnosis of NC. PCR may be particularly helpful for diagnosing extraparenchymal NC when neuroimaging techniques have failed. Classification of evidence: This study provides Class III evidence that CSF PCR can accurately identify patients with extraparenchymal NC