Pre-stimulus alpha activity modulates face and object processing in the intra-parietal sulcus, a MEG study

Face perception is crucial in all social animals. Recent studies have shown that pre-stimulus oscillations of brain activity modulate the perceptual performance of face vs. non-face stimuli, specifically under challenging conditions. However, it is unclear if this effect also occurs during simple tasks, and if so in which brain regions. Here we used magnetoencephalography (MEG) and a 1-back task in which participants decided if the two sequentially presented stimuli were the same or not in each trial. The aim of the study was to explore the effect of pre-stimulus alpha oscillation on the perception of face (human and monkey) and non-face stimuli. Our results showed that pre-stimulus activity in the left occipital face area (OFA) modulated responses in the intra-parietal sulcus (IPS) at around 170 ms after the presentation of human face stimuli. This effect was also found after participants were shown images of motorcycles. In this case, the IPS was modulated by pre-stimulus activity in the right OFA and the right fusiform face area (FFA). We conclude that pre-stimulus modulation of post-stimulus response also occurs during simple tasks and is therefore independent of behavioral responses

BCG scar formation and test results in two generations

Introduction: Considering that BCG injection in newborns is part of TB control program in Iran many years ago, we aimed to compare prevalence of childhood BCG vaccination scar with previous study and asses influence of household crowding on TST result. Aims: Considering that over time there is likely to reduce the immune response, two groups of subjects were selected among young and middle aged. Methods and Material: This cross sectional study was conducted in Zia Abad of Qazvin (a province of Iran) during year 2008. 261 participants randomly were selected (139 asymptomatic children (12-16 y) and 122 adults (40-50 y)). A questionnaire was used to obtain prior histories of BCG vaccination, known exposure to tuberculosis, prior acquired of TB, symptoms of TB disease and household crowding. BCG vaccine scar was ascertained and all participants were tested with 5TU-PPD. Reactions of 10 mm or more were considered positive. Statistical analysis used: Using student t test, chi square and Fisher's exact test, the collected data was analyzed. Results: BCG scar was observed in 78.4 of participant (91.4 children vs. 78.6 adults) which the difference was significant. Twenty three (16.5) of children and 24 (19.7) of adults had tuberculin reactivity of �10 mm. In children and parent groups, positivity of TST had significant direct association with presence of BCG scar and crowding. Conclusions: Most vaccinated children had a scar. Our results demonstrate that a TST applied after BCG vaccination usually produces a reaction of <10 mm. In addition, there is a significant relationship between the tuberculin reactivity and both presence of BCG scar and crowding among children and adult groups. © 2011, Shiraz E Medical Journal. All right reserved