Prefrontal control over motor cortex cycles at beta-frequency during movement inhibition

A fully adapted behavior requires maximum efficiency to inhibit processes in the motor domain [ 1 ]. Although a number of cortical and subcortical brain regions have been implicated, converging evidence suggests that activation of right inferior frontal gyrus (r-IFG) and right presupplementary motor area (r-preSMA) is crucial for successful response inhibition [ 2, 3 ]. However, it is still unknown how these prefrontal areas convey the necessary signal to the primary motor cortex (M1), the cortical site where the final motor plan eventually has to be inhibited or executed. On the basis of the widely accepted view that brain oscillations are fundamental for communication between neuronal network elements [ 4–6 ], one would predict that the transmission of these inhibitory signals within the prefrontal-central networks (i.e., r-IFG/M1 and/or r-preSMA/M1) is realized in rapid, periodic bursts coinciding with oscillatory brain activity at a distinct frequency. However, the dynamics of corticocortical effective connectivity has never been directly tested on such timescales. By using double-coil transcranial magnetic stimulation (TMS) and electroencephalography (EEG) [ 7, 8 ], we assessed instantaneous prefrontal-to-motor cortex connectivity in a Go/NoGo paradigm as a function of delay from (Go/NoGo) cue onset. In NoGo trials only, the effects of a conditioning prefrontal TMS pulse on motor cortex excitability cycled at beta frequency, coinciding with a frontocentral beta signature in EEG. This establishes, for the first time, a tight link between effective cortical connectivity and related cortical oscillatory activity, leading to the conclusion that endogenous (top-down) inhibitory motor signals are transmitted in beta bursts in large-scale cortical networks for inhibitory motor control

Effects of bisphenol A administration during critical stages of sexual development

El bisfenol A (BPA) es un compuesto estrogénico utilizado en la fabricación de plásticos policarbonatos, que tiene efectos deletéreos sobre el eje reproductor de los individuos expuestos y el de su descendencia. El BPA actuaría sobre el eje hipotálamo-hipófiso-gonadal de ratas hembra modificando sus procesos de maduración. El objetivo del presente trabajo fue estudiar el efecto del BPA sobre la maduración del eje reproductor de ratas hembra peripúberes expuestas a este compuesto desde el inicio de la gestación y durante la lactancia (Grupo 1, 2,5 mg/kg/día)) y otro grupo (Grupo 2, 6,0 mg/kg/día) expuesto desde los 21 días y hasta los 30 días de edad. Se administró BPA en el agua de bebida o etanol al 0,1% (grupo control), (n=10/grupo). Se determinó LH, FSH (RIA, ng/ml), estradiol (ELISA, pg/ml), se evaluaron peso corporal y pesos relativos de útero y ovario. Se realizó estudio histológico de cortes de ovario y útero. Grupo 1, los niveles de LH y estradiol aumentaron significativamente (Control: 11 ± 1,0 vs. BPA: 40 ± 4,0, p<0,001; Control: 20 ± 0,5 vs. BPA: 40 ± 2,0, p<0,0001), mientras los de FSH mostraron tendencia al aumento pero éste no fue significativo. Los pesos corporales y el peso relativo del ovario no se modificaron con el tratamiento. El estudio histológico mostró mayor número de folículos maduros y desarrollo de células de la teca y epitelio cilíndrico en útero de los animales tratados. Grupo 2, LH y estradiol aumentaron significativamente (Control: 3,3 ± 0,3 vs. BPA: 5,1 ± 0,3, p<0,01; Control: 25,0 ± 0,5 vs. BPA: 27,1 ± 0,7, p<0,05). La FSH, si bien mostró tendencia a aumentar, ésta no fue significativa. Los pesos corporales y los pesos relativos de ovario y útero no se modificaron con este tratamiento. En la histología se observa mayor desarrollo de la teca interna y un mayor número de folículos maduros en los animales tratados. No se encontraron diferencias evidentes en el alto del epitelio uterino. La exposición aguda o crónica a BPA en etapas clave de la maduración sexual modifica la actividad del eje reproductor. Los resultados obtenidos sugieren que el BPA ejercería su efecto estrogénico, actuando sobre los mecanismos de retroalimentación positivos.Bisphenol A (BPA) is an estrogenic compound used in the manufacture of polycarbonate plastic. It has deleterious effects on the reproductive axis in human and wildlife, both in individuals exposed to it and their descendants. Evidence suggests that BPA exerts its influence on the hypothalamic-pituitary-gonadal axis of female rats by interfering with its maturation process. The aim of the present study was to analyse the effect of BPA on maturation of the hypothalamo-pituitary-gonadal axis of peripuberal female rats, exposed to it since the beginning of the gestation and during the lactation period (Group 1, 2.5 mg/kg/day), and from the age of 21 days till the age of 30 (Group 2, 6.0 mg/kg/day). The animals were treated with BPA or 0.1% ethanol (Control Group) in their drinking water (n=10/grupo). LH, FSH (RIA, ng/ml) and estradiol (ELISA, pg/ml) were measured in serum. Ovaries and uterus relative weights were obtained. Histological studies were performed on several sections of uterus and ovaries. Group 1, LH and estradiol serum levels increased significantly (Control: 11 ± 1.0 vs. BPA: 40 ± 4.0, p<0.001; Control: 20 ± 0.5 vs BPA: 40 ± 2.0, p<0.0001). FSH levels showed an increasing trend as well, but this was not statistically significant. Corporal weights and ovaries relative weights were not modified by treatment. Histological studies showed an increase in the total number of mature follicles, and development of the theca cells and ovarian stroma, in animals exposed to BPA. Group 2, LH and estradiol serum levels increased significantly (Control: 3.3 ± 0.3 vs. BPA: 5.1 ± 0.3, p<0.01; Control: 25.0 ± 0.5 vs. BPA: 27.1 ± 0.7, p<0.05). Although FSH levels exhibited an increasing trend, this did not reach statistical significance. Corporal weights and ovaries and uterus relative weights were not modified by treatment. Histological studies revealed major development of the internal theca, and an increase in the number of mature follicles, in those animals under treatment. No significant differences were found in the height of the epithelium of the uterus. Acute or chronic exposure to BPA during critical stages of sexual development modifies the activity of the reproductive axis. The results obtained suggest that BPA may exert its estrogenic effect, acting on the positive feedback mechanism.Fil: Cardoso, Nancy Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; ArgentinaFil: Pandolfi, Matias. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Embriología Animal; ArgentinaFil: Ponzo, Osvaldo. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; ArgentinaFil: Carbone, Silvia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Peñalba, Romina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; ArgentinaFil: Dicugno. Mariana. Universidad de Buenos Aires. Facultad de Medicina. Sede Hospital Britanico Bs.as; ArgentinaFil: Scacchi, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Reynoso, Roxana. Hospital Británico; Argentin

Different effects by sex on hypothalamic-pituitary axis of prepubertal offspring rats produced by in utero and lactational exposure to di-(2-ethylhexyl) phthalate (DEHP)

This study investigated the effect of pre and perinatal exposure to di-(2-ethylhexyl) phthalate (DEHP) on the neuroendocrine parameters that regulate reproduction in prepubertal male and female rats. DEHP at doses of 3 and 30 mg/kg. bw/day was administered orally in the drinking water to dam rats since pregnancy onset until the moment of pups sacrifice at 15 days of age. In these animals gonadotropin serum level and the hypothalamic contents of the amino acids aspartate, glutamate and gamma-aminobutyric acid were determined. No changes in gonadotropin levels and amino acid neurotransmitters were detected at the low dose in both sexes. However, DEHP administered at high dose (30 mg/kg bw/day) to dams produced a significant decrease in the inhibitory neurotransmitter GABA and an increase in the stimulatory neurotransmitter aspartate in prepubertal male offspring rats. These modifications were accompanied by gonadotropin serum levels increase. On the contrary, in treated female rats this chemical increased both, aspartate and GABA, which exert a characteristic stimulatory action on gonadotropin in 15-day-old normal females. This study provides new data about changes produced by DEHP on the hypothalamic amino acid neurotransmitters involved in the neuroendocrine reproductive regulation, in prepubertal male and female rat offspring from dams exposed during gestational and lactational periods. These alterations induced by DEHP exposure could be related to the gonadotropin modifications also described in this work, and with changes in the production of sexual hormones previously reported by other authors.Fil: Carbone, Silvia Elena. Universidad Favaloro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Samaniego, Yanina A.. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Cutrera, Rodolfo Angel. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Reynoso, R.. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Cardoso, N.. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Scacchi, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; ArgentinaFil: Moguilevsky, Jaime Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Favaloro; ArgentinaFil: Ponzo, Osvaldo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentin

The incidence of vestibular neuritis in Italy

ObjectiveThis study aims to estimate the incidence of Vestibular neuritis (VN) in three different districts in Italy, its epidemiological features, and the prevalence of comorbidities associated with it. MethodsAn observational prospective study of 198 patients referred to ENT departments in Siena, Grosseto, and Cuneo was carried out over a 2-year period. Each patient underwent a complete otoneurologic examination in the first 48 h from the onset of symptoms and a brain MRI in the early stages of the disease. The follow-up lasted for 1 year. ResultsThe total VN incidence rate of the three municipalities was 48.497 (95% CI: 48.395-48.598) and its standardized value was 53.564 (95% CI: 53.463-53.666). The total VN incidence rate for the whole sample (municipality and district of the three centers) was 18.218 (95% CI: 18.164-18.272), and its standardized value was 20.185 (95% CI: 20.129-20.241). A significant difference was highlighted between patients living in the city compared to those living in the surrounding area (p &lt; 0.000), this may be due to the ease of reaching the otoneurological referral center. ConclusionThe total incidence rate for the three municipalities was 48.497. This result is higher than previously reported studies

Modified atmosphere and cold storage for postharvest conservation of 'Niagara Rosada' table grape

O objetivo deste trabalho foi avaliar os efeitos da atmosfera modificada na conservação pós‑colheita da uva 'Niagara Rosada' armazenada sob refrigeração, em dois experimentos. No primeiro experimento avaliou-se o acondicionamento de cachosnas seguintes embalagens: papelão ondulado (testemunha); tereftalato de polietileno (PET); cloreto de polivinila (PVC) 17 μm; polietileno linear de baixa densidade (PELBD) 25 µm; e PELBD 50 µm. Em outro experimento, avaliaram-se os sistemas de acondicionamento: sacolas de plástico abertas (testemunha); polietileno de baixa densidade (PEBD) 25 μm; PEBD 25 µm, com injeção de mistura gasosa (21% O2/5% CO2); PEBD 25 µm (21% O2/10% CO2); PEBD 25 µm (21% O2/20% CO2). Os cachos foram armazenados a 1±1°C e 90±5% de umidade relativa (UR) por 28 dias, seguido de armazenamento em condições do ambiente (25±2°C e 80±5% UR). Os cachos foram avaliados quanto à perda de massa de matéria fresca, firmeza, cor das bagas, esbagoamento, sólidos solúveis totais (SST), acidez titulável (AT), relação SST/AT e incidência de podridões. O filme PELBD 50 µm, a partir do 14º dia a 1°C, seguido por mais três dias a 25°C, causou a fermentação dos cachos. As embalagens PELBD 25 µm, com ou sem injeção de mistura gasosa, e PVC 17 µm reduzem a perda de massa de matéria fresca dos cachos, mas não reduzem o esbagoamento e a incidência de podridões.The objective of this work was to evaluate the effect of the modified atmosphere, on the storage life of 'Niagara Rosada' Table grape kept under refrigeration in two experiments. In the first one, grape clusters stored in different package materials were evaluated: corrugated cardboard boxes, polyethylene tereftalate (PET); 17-μm  polyvinyl chloride (PVC); 25-μm low density linear polyethylene film (PELDB); and 50-μm PELDB. On a second assay, different packaging systems were evaluated: opened plastic bags; 25-μm low density polyethylene film (PEBD); 25-μm PEBD, with injection of gas mixture (21% O2/5% CO2), 25-μm PEBD (21% O2/10% CO2); 25-μm PEBD (21% O2/20% CO2). The grape clusters were stored at 1±1°C and 90 ± 5% relative humidity (RH) for 28 days, followed by a storage period at room conditions at 25 ± 2ºC and 80± 5% RH. Clusters were evaluated for weight loss, firmness, color of the berries, percentage of detached berries, total soluble solids (SST), titratable acidity (TA), SST/TA, and rot incidence. Polyethylene film of 50-μm, from the 14th day at 1°C, with an additional period of 3 days at 25°C, caused fruit fermentation. The 25-μm PELBD, with or without gas injection, and 17-μm PVC films reduce clusters weight loss, but do not reduce berry detaching and rot incidence

Transcranial magnetic stimulation of the precuneus enhances memory and neural activity in prodromal Alzheimer's disease

Memory loss is one of the first symptoms of typical Alzheimer's disease (AD), for which there are no effective therapies available. The precuneus (PC) has been recently emphasized as a key area for the memory impairment observed in early AD, likely due to disconnection mechanisms within large-scale networks such as the default mode network (DMN). Using a multimodal approach we investigated in a two-week, randomized, sham-controlled, double-blinded trial the effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) of the PC on cognition, as measured by the Alzheimer Disease Cooperative Study Preclinical Alzheimer Cognitive Composite in 14 patients with early AD (7 females). TMS combined with electroencephalography (TMS-EEG) was used to detect changes in brain connectivity. We found that rTMS of the PC induced a selective improvement in episodic memory, but not in other cognitive domains. Analysis of TMS-EEG signal revealed an increase of neural activity in patients' PC, an enhancement of brain oscillations in the beta band and a modification of functional connections between the PC and medial frontal areas within the DMN. Our findings show that high-frequency rTMS of the PC is a promising, non-invasive treatment for memory dysfunction in patients at early stages of AD. This clinical improvement is accompanied by modulation of brain connectivity, consistently with the pathophysiological model of brain disconnection in AD

Atmosfera modificada e refrigeração para conservação pós-colheita de uva 'Niagara Rosada'

O objetivo deste trabalho foi avaliar os efeitos da atmosfera modificada na conservação pós-colheita da uva 'Niagara Rosada' armazenada sob refrigeração, em dois experimentos. No primeiro experimento avaliou-se o acondicionamento de cachos nas seguintes embalagens: papelão ondulado (testemunha); tereftalato de polietileno (PET); cloreto de polivinila (PVC) 17 &#956;m; polietileno linear de baixa densidade (PELBD) 25 &#956;m; e PELBD 50 &#956;m. Em outro experimento, avaliaram-se os sistemas de acondicionamento: sacolas de plástico abertas (testemunha); polietileno de baixa densidade (PEBD) 25 &#956;m; PEBD 25 &#956;m, com injeção de mistura gasosa (21% O2/5% CO2); PEBD 25 &#956;m (21% O2/10% CO2); PEBD 25 &#956;m (21% O2/20% CO2). Os cachos foram armazenados a 1±1°C e 90±5% de umidade relativa (UR) por 28 dias, seguido de armazenamento em condições do ambiente (25±2°C e 80±5% UR). Os cachos foram avaliados quanto à perda de massa de matéria fresca, firmeza, cor das bagas, esbagoamento, sólidos solúveis totais (SST), acidez titulável (AT), relação SST/AT e incidência de podridões. O filme PELBD 50 &#956;m, a partir do 14º dia a 1°C, seguido por mais três dias a 25°C, causou a fermentação dos cachos. As embalagens PELBD 25 &#956;m, com ou sem injeção de mistura gasosa, e PVC 17 &#956;m reduzem a perda de massa de matéria fresca dos cachos, mas não reduzem o esbagoamento e a incidência de podridões

Evidence of reproductive disruption associated with neuroendocrine changes induced by UV–B filters, phtalates and nonylphenol during sexual maturation in rats of both gender

Endocrine disruptors (EDs) are exogenous substances or xenoestrogens natural or synthetic, capable of interacting with different systems and altering their normal hormonal regulation, being the reproductive system one of the most affected. EDs produce their effects not only by acting on nuclear steroid receptors, but also on membrane receptors, steroidal and non-steroidal synthetic enzymatic pathways and/or metabolism. The incorporation to the body depend on each EDs, which are liposoluble and easily deposited in the tissue; thus ensuring a prolonged accumulation and release, even when the exposure is not continuous. In addition to cross the placenta, EDs may act in the offspring during the reproductive system formation and maturation key stages and its regulatory mechanisms. The effects of EDs can be multiple, but most acts mediating estrogenic and/or antiandrogenic effect. Three groups of EDs are widely used: in plastics (phtalates), sunscreens (cinnamate and methylbenzylcamphor), and detergents (nonylphenol). In this paper we review the effects of the exposure to these environmental chemicals on the reproductive system and the possible mechanisms by which they occur, focusing in the hypothalamic–pituitary neuroendocrine mechanisms that regulate the reproductive system.Fil: Ponzo, Osvaldo Juan. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina;Fil: Carbone, Silvia Elena. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Endocrinología; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina