Age-related positivity effect of emotional attention: time and frequency domain.

Compared with their younger counterparts, older adults are inclined to allocate more attentional resources to positive over negative materials. This age-related positivity effect has been reported in various experimental paradigms; however, studies have not investigated the attention stage at which it appears or its potential neural mechanism. Thus, we investigated the time and frequency domain dynamics of younger and older adults during emotional attention processes. We obtained electroencephalography oscillation and event-related potential data for 20 older and 20 younger participants while they performed an emotional dot-probe task. We focused our time and frequency domain dynamics analyses on the posterior regions as a key structure for facial emotion perception and the frontal regions as a crucial structure for cognitive control. In the time domain, older adults showed an initial attentional shift to happy-related stimuli, whereas their younger counterparts did not demonstrate emotional modulation, as reflected by the N2pc component. The time-frequency decomposition was analyzed for the N2pc time window. The results showed that compared with younger adults, older adults showed an increased alpha power for happy faces in the right-posterior regions. Moreover, a parallel pattern was seen in frontal theta activity. The current findings highlight how electrocortical activity of the brain might moderate the tendency to prioritize positive information among healthy older adults. The emergence of an age-related positivity effect may be related to frontal cognitive control processing. These findings provide insight into the prevention and treatment of unsuccessful aging, such as late-life depression and anxiety.

The effect of magnetic guiding BMSCs on hypoxic-ischemic brain damage via magnetic resonance imaging evaluation.

Hypoxic-ischemic brain damage (HIBD) is a critical disease in pediatric neurosurgery with high mortality rate and frequently leads to neurological sequelae. The role of bone marrow mesenchymal stem cells (BMSCs) in neuroprotection has been recognized. However, using the imaging methods to dynamically assess the neuroprotective effects of BMSCs is rarely reported. In this study, BMSCs were isolated, cultured and identified. Flow cytometry assay had shown the specific surface molecular markers of BMSCs, which indicated that the cultivated cells were purified BMSCs. The results demonstrated that CD29 and CD90 were highly expressed, whilst CD45 and CD11b were negatively expressed. Further, BMSCs were transplanted into Sprague Dawley (SD) rats established HIBD via three ways, including lateral ventricle (LV) injection, tail vein (TV) injection, and LV injection with magnetic guiding. Magnetic resonance imaging (MRI) was used to monitor and assess the treatment effect of super paramagnetic iron oxide (SPIO)-labeled BMSCs. The mean kurtosis (MK) values from diffusion kurtosis imaging (DKI) exhibited the significant differences. It was found that the MK value of HIBD group increased compared with that in Sham. At the meantime, the MK values of LV + HIBD, TV + HIBD and Magnetic+LV + HIBD groups decreased compared with that in HIBD group. Among these, the MK value reduced most significantly in Magnetic+LV + HIBD group. MRI illustrated that the treatment effect of Magnetic+LV + HIBD group was best. In addition, HE staining and TUNEL assay measured the pathological changes and apoptosis of brain tissues, which further verified the MRI results. All data suggest that magnetic guiding BMSCs, a targeted delivery way, is a new strategic theory for HIBD treatment. The DKI technology of MRI can dynamically evaluate the neuroprotective effects of transplanted BMSCs in HIBD.