Zhaoqi Hu

The human brain optimises cognitive resource allocation to enhance the processing speed and efficiency of vital information for better survival and adaptation in response to threat signals. Previous studies found that fearful expressions, as visual cues signalling threats, can not only have advantages in entering and remaining in awareness, but also enhance subsequent perceptual processing of low-spatial-frequency (LSF) information. However, it remains unknown whether the enhanced perceptual processing of LSF induced by fearful expressions also grants LSF information a competitive advantage in awareness. To this end, we employed a binocular rivalry paradigm to measure awareness of Gabor patches with low or high spatial frequencies following the rapid priming of fearful versus neutral expressions. The results revealed that the relative dominance of LSF over high-spatial-frequency (HSF) Gabor patches was markedly heightened following brief exposure to fearful compared with neutral expressions. This effect was found for both upright and inverted expressions, indicating it is independent of face configuration. Our study thus suggests a feature-based perceptual optimisation mechanism with evolutionary significance, potentially optimising cognitive resource allocation in threatening situations.

© 2015 Elsevier Inc.The breakthrough of induced pluripotent stem cell technology has raised the possibility that patient-specific iPSCs may become a renewable source of autologous cells for cell therapy without the concern of immune rejection. However, the immunogenicity of autologous human iPSC -derived cells is not well understood. Using a humanized mouse model reconstituted with a functional human immune system, we demonstrate that most teratomas formed by autologous integration-free hiPSCs exhibit local infiltration of antigen-specific T cells and associated tissue necrosis, indicating immune rejection of certain hiPSC-derived cells. In this context, autologous hiPSC-derived smooth muscle cells appear to be highly immunogenic, while autologous hiPSC-derived retinal pigment epithelial cells are immune tolerated even in non-ocular locations. This differential immunogenicity is due in part to abnormal expression of immunogenic antigens in hiPSC-derived SMCs, but not in hiPSC-derived RPEs. These findings support the feasibility of developing hiPSC-derived RPEs for treating macular degeneration.