Research / children's health

The article provides detailed information from a study that suggests environmental exposure to airborne manganese (Mn) is neurotoxic, especially when inhaled, and is inversely associated with intellectual function in young school-age children. Entering into the body through the lungs, airborne Mn may access the brain directly through olfactory uptake. This cross-sectional study measured the environmental exposure to airborne Mn resulting from mining and processing in Hidalgo State in central Mexico, and explored its association with the intellectual function of school-age children

Between-site reliability of startle prepulse inhibition across two early psychosis consortia

Prepulse inhibition (PPI) and reactivity of the acoustic startle response are widely used biobehavioral markers in psychopathology research. Previous studies have demonstrated that PPI and startle reactivity exhibit substantial within-site stability; between-site stability, however, has not been established. In two separate consortia investigating biomarkers of early psychosis, traveling subjects studies were performed as part of quality assurance procedures in order to assess the fidelity of data across sites. In the North American Prodromal Longitudinal Studies (NAPLS) Consortium, 8 normal subjects traveled to each of the 8 NAPLS sites and were tested twice at each site on the startle PPI paradigm. In preparation for a binational study, 10 healthy subjects were assessed twice in both San Diego and Mexico City. Intraclass correlations between and within sites were significant for PPI and startle response parameters, confirming the reliability of startle measures across sites in both consortia. There were between site differences in startle magnitude in the NAPLS study that did not appear to be related to methods or equipment. In planning multi-site studies, it is essential to institute quality assurance procedures early and establish between site reliability to assure comparable data across sites

Estudio de la atención involuntaria, mediante potenciales relacionados con eventos, en pacientes con enfermedad de Parkinson /

\ua0tesis que para obtener el grado de Doctor en Psicología, presenta Rodolfo Solís Vivanco ; asesor Ricardo Garcell Josefina, Roberto Agustín Prado Alcalá, Mario Arturo Rodríguez Camacho, María Asunción Corsi Cabrera, Irma Yolanda Del Río Portilla. 127, [17] páginas :\ua0ilustraciones. Doctorado en Psicología\ua0UNAM, Facultad de Psicología,\ua0201

Top–Down Control of Alpha Phase Adjustment in Anticipation of Temporally Predictable Visual Stimuli

Alpha oscillations (8–14 Hz) are proposed to represent an active mechanism of functional inhibition of neuronal processing. Specifically, alpha oscillations are associated with pulses of inhibition repeating every ∼100 msec. Whether alpha phase, similar to alpha power, is under top–down control remains unclear. Moreover, the sources of such putative top–down phase control are unknown. We designed a cross-modal (visual/auditory) attention study in which we used magnetoencephalography to record the brain activity from 34 healthy participants. In each trial, a somatosensory cue indicated whether to attend to either the visual or auditory domain. The timing of the stimulus onset was predictable across trials. We found that, when visual information was attended, anticipatory alpha power was reduced in visual areas, whereas the phase adjusted just before the stimulus onset. Performance in each modality was predicted by the phase of the alpha oscillations previous to stimulus onset. Alpha oscillations in the left pFC appeared to lead the adjustment of alpha phase in visual areas. Finally, alpha phase modulated stimulus-induced gamma activity. Our results confirm that alpha phase can be top–down adjusted in anticipation of predictable stimuli and improve performance. Phase adjustment of the alpha rhythm might serve as a neurophysiological resource for optimizing visual processing when temporal predictions are possible and there is considerable competition between target and distracting stimuli

Descripción del marco metodológico para la construcción de matrices de insumo-producto a partir de los cuadros de oferta y utilización: una aplicación para el caso de Panamá

La proliferación de información estadística basada en cuentas nacionales se ha traducido en un resurgimiento importante del análisis cuantitativo basado en modelos de insumo-producto. La elaboración de matrices de insumo-producto se sustenta en información proveniente de cuentas nacionales. En particular, los cuadros de oferta y utilización proporcionan los datos fundamentales requeridos para su elaboración, debido a que constituyen un sistema contable organizado que relaciona coherentemente los productos, sectores económicos e industrias. Precisamente en este punto es en donde surge la motivación central del presente estudio. De los 10 países a los cuales la Sede Subregional de la CEPAL en México da seguimiento, sólo México, Costa Rica y Honduras elaboran matrices de insumo-producto públicamente disponibles, en tanto que los restantes países generan sólo cuadros de oferta y utilización anuales cuya frecuencia de actualización varía de acuerdo al país en cuestión. Consecuentemente, el objetivo principal del presente artículo es presentar la metodología para elaborar matrices de insumo-producto a partir de cuadros de oferta y utilización, y de esta forma extender el análisis que es posible realizar utilizando este instrumental a una mayor cantidad de países de la región.Resumen .-- Introducción .-- I. Cuadros de oferta y utilización .-- II. Metodología de ransformación de los cuadros de oferta y utilización a una matriz de insumo-producto .-- III. Ejemplificación de la metodología de transformación de los cuadros de oferta y utilización a una matriz de insumo-producto con un caso simple .-- IV. Aplicación de la metodología para la transformación de los cuadros de oferta y utilización a una matriz de insumo-producto para el caso de Panamá 2012

Cognitive impairment in an adult Mexican population non-occupationally exposed to manganese

The main finding of this study is the presence of attention impairments associated with high levels of air Manganese (Mn) exposure. These results confirm previous studies, in which cognitive impairment is reported for an exposed population. The study was carried out in a mining district located in Hidalgo State, Mexico, with 288 adult participants. Air and blood Mn concentrations were determined, and neuropsychological tests were administered to explore cognitive functions and depression

Brain oscillations reveal impaired novelty detection from early stages of Parkinson's disease

The identification of reliable biomarkers for early diagnosis and progression tracking of neurodegenerative diseases has become an important objective in clinical neuroscience in the last years. The P3a event-related potential, considered as the neurophysiological hallmark of novelty detection, has been shown to be reduced in Parkinson's disease (PD) and proposed as a sensitive measure for illness duration and severity. Our aim for this study was to explore for the first time whether impaired novelty detection could be observed through phase- and time-locked brain oscillatory activity at early PD. Twenty-seven patients with idiopathic PD at early stages (disease duration <5 years and Hoehn and Yahr stage <3) were included. A healthy control group (n = 24) was included as well. All participants performed an auditory involuntary attention task including frequent and deviant tones while a digital EEG was obtained. A neuropsychological battery was administered as well. Time-frequency representations of power and phase-locked oscillations and P3a amplitudes were compared between groups. We found a significant reduction of power and phase locking of slow oscillations (3–7 Hz) for deviant tones in the PD group compared to controls in the P3a time range (300–550 ms). Also, reduced modulation of late induced (not phase locked) alpha-beta oscillations (400–650 ms, 8–25 Hz) was observed in the PD group after deviant tones onset. The P3a amplitude was predicted by years of evolution in the PD group. Finally, while phase-locked slow oscillations were associated with task behavioral distraction effects, induced alpha-beta activity was related to cognitive flexibility performance. Our results show that novelty detection impairment can be identified in neurophysiological terms from very early stages of PD, and such impairment increases linearly as the disease progresses. Also, induced alpha-beta oscillations underlying novelty detection are related to executive functioning. Keywords: Parkinson's disease, Oscillations, P3a, Novelty, Biomarke

Non-inflammatory cerebrospinal fluid delays the diagnosis and start of immunotherapy in anti-NMDAR encephalitis

ABSTRACT Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a form of autoimmune encephalopathy that presents with a wide variety of symptoms, including neuropsychiatric manifestations. The authors’ aim for this study was to analyze the results of paraclinical studies of patients with a diagnosis of anti-NMDAR encephalitis and the association between symptom onset and diagnosis, and start of immunotherapy. Retrospective data of 29 patients with anti-NMDAR encephalitis were gathered and analyzed. Abnormal EEG was found in 27 patients (93.1%), whereas MRI was abnormal in 19 patients (65.5%). In contrast, an inflammatory pattern on CSF analysis was found in only 13 patients (44.8%). The absence of pleocytosis or increased proteins in the CSF was associated with a longer time from symptom onset to diagnosis and treatment (p = 0.003). The authors conclude that noninflammatory CSF may delay the correct diagnosis and start of immunotherapy in anti-NMDAR encephalitis. In the presence of suggestive clinical features, extensive studies including EEG are recommended