Protective effect of glutamic-oxaloacetic transaminase on hippocampal neurons in Alzheimer's disease using model mice.

Alzheimer's disease (AD), a neurodegenerative disease affecting the elderly, frequently causes cognitive impairment and memory decline, and there are currently no effective therapeutic drugs available. Glutamate excitotoxicity is one of the pathogeneses of AD, and there is evidence that glutamic-oxaloacetic transaminase (GOT) can significantly reduce glutamate concentrations in the hippocampi of mice, but its role in APP/PS1 transgenic mice is unknown. We investigated the improvement of neurological function and related protein expression following subcutaneous injection of GOT in mice with AD. We performed immunohistochemical staining on the brain tissue of 3-, 6-, and 12-month-old mice and found that the content of the ß-amyloid protein Aß1-42 in the 6 months old GOT treatment group was significantly reduced. Meanwhile, the APP-GOT group outperformed the APP group in the water maze and spatial object recognition experiments. The number of neurons in the hippocampal CA1 area of the APP-GOT group increased when compared to the APP group according to Nissl staining. Electron microscopic examination of the hippocampal CA1 area demonstrated that the number of synapses in the APP-GOT group was more than that in the APP group, and the mitochondrial structure was relatively complete. Finally, the protein content of the hippocampus was detected. In comparison to the APP group, SIRT1 content increased in the APP-GOT group whereas Aß1-42 content decreased, and Ex527 could reverse this trend. These results suggest that GOT can significantly improve the cognitive function of mice in the early stage of AD, and the underlying mechanism may be through decreasing Aß1-42 and increasing SIRT1 expressions.

The Uncanny Valley Phenomenon and the Temporal Dynamics of Face Animacy Perception.

Human replicas highly resembling people tend to elicit eerie sensations-a phenomenon known as the uncanny valley. To test whether this effect is attributable to people's ascription of mind to (i.e., mind perception hypothesis) or subtraction of mind from androids (i.e., dehumanization hypothesis), in Study 1, we examined the effect of face exposure time on the perceived animacy of human, android, and mechanical-looking robot faces. In Study 2, in addition to exposure time, we also manipulated the spatial frequency of faces, by preserving either their fine (high spatial frequency) or coarse (low spatial frequency) information, to examine its effect on faces' perceived animacy and uncanniness. We found that perceived animacy decreased as a function of exposure time only in android but not in human or mechanical-looking robot faces (Study 1). In addition, the manipulation of spatial frequency eliminated the decrease in android faces' perceived animacy and reduced their perceived uncanniness (Study 2). These findings link perceived uncanniness in androids to the temporal dynamics of face animacy perception. We discuss these findings in relation to the dehumanization hypothesis and alternative hypotheses of the uncanny valley phenomenon.

Human Perception of Animacy in Light of the Uncanny Valley Phenomenon.

The uncanny valley hypothesis by Japanese roboticist Masahiro Mori posits a nonlinear relation between human replicas' human likeness and the emotional responses they elicit. In three studies, we corroborated the uncanny valley hypothesis, using the uncanny phenomenon as a vehicle to shed a new light on human animacy perception. In Study 1, 62 participants rated emotional responses and human likeness of 89 artificial and human faces. In Study 2, another 62 participants conducted a visual looming task with the same 89 faces allowing for the measurement of perceived threat. Results support the uncanny valley hypothesis, suggesting that the uncanny feeling may serve a function to wary humans of the potential danger of entities crossing the animate-inanimate boundary. In Study 3, 36 participants sorted faces as either real or unreal as quickly as possible in a reaction time sorting task allowing for the measurement of categorical uncertainty associated with animacy perception. Faces associated with longer sorting reaction times were also those associated with the highest ratings of negative emotions, suggesting that categorical uncertainty in animacy detection is related to the uncanny feeling. Results are discussed in light of human animacy perception and new directions for future research are suggested.