Recognition of high-frequency steady-state visual evoked potential for brain-computer interface / 生物医学工程学杂志

Coding with high-frequency stimuli could alleviate the visual fatigue of users generated by the brain-computer interface (BCI) based on steady-state visual evoked potential (SSVEP). It would improve the comfort and safety of the system and has promising applications. However, most of the current advanced SSVEP decoding algorithms were compared and verified on low-frequency SSVEP datasets, and their recognition performance on high-frequency SSVEPs was still unknown. To address the aforementioned issue, electroencephalogram (EEG) data from 20 subjects were collected utilizing a high-frequency SSVEP paradigm. Then, the state-of-the-art SSVEP algorithms were compared, including 2 canonical correlation analysis algorithms, 3 task-related component analysis algorithms, and 1 task discriminant component analysis algorithm. The results indicated that they all could effectively decode high-frequency SSVEPs. Besides, there were differences in the classification performance and algorithms' speed under different conditions. This paper provides a basis for the selection of algorithms for high-frequency SSVEP-BCI, demonstrating its potential utility in developing user-friendly BCI.

Experimental study of protective effect of recombinant human hepatocyte growth factor on heart graft preservation in rats / 中国医师杂志

Objective To observe the effect of hepatocyte growth factor on preserving isolated heart of rats. Methods Forty rats were random divided into two groups: Control group(n=20)which rat hearts were isolated and preserved in 4℃HTK solution, and experimental group(n=20)which rat hearts were isolated and preserved in 4℃ HTK+rh-HGF(100μg/L)solution. Before operation and rat hearts were subjected to 8 hours(groupA,C)or 12 hours(group B,D)hypothermic storage followed by 5 minutes of normothermic reperfusion onmodifiedLangendorff-Neely model. The recovery rate of cardiac function after myocardial preservation, such as LVSP and LVDP and±dp/dt max and the changes of CK,LDH,NO and ET were measured. Cell apoptosis was detected by TUNEL staining and the expression of c-met was analyzed by immunohistochemical method. The expression change of bcl-2 mRNA was examined by RT-PCR. Results Compared with control group, experimental group showed that a significantly higher recovery rate of LVSP,LVDP and±dp/dt max(P＜0.01) and lower rate of TUNEL positive cardiomyocytes(P＜0.01) after reperfusion. The leakage of CK and LDH was significant lower than that of control group(P＜0.01). Immunohistochemical analysis revealed that c-met receptor expression was stronger in the HGF-treated myocardium than that in the non HGF-treated myocardium after storage, and this was associated with a stronger expression of bcl-2 mRNA. Conclusion The administration of rh-HGF before storage improved cardiac function after prolonged myocardial preservation by preventing apoptosis and enhancing expression of bcl-2 mRNA. Thus, the addition of rh-HGF in the storage solution may be a promising strategy for prolonged heart graft preservation.