In recent years, hybrid brain-computer interfaces (BCIs) have gained significant attention due to their demonstrated advantages in increasing the number of targets and enhancing robustness of the systems. However, Existing studies usually construct BCI systems using intense auditory stimulation and strong central visual stimulation, which lead to poor user experience and indicate a need for improving system comfort. Studies have proved that the use of peripheral visual stimulation and lower intensity of auditory stimulation can effectively boost the user's comfort. Therefore, this study used high-frequency peripheral visual stimulation and 40-dB weak auditory stimulation to elicit steady-state visual evoked potential (SSVEP) and auditory steady-state response (ASSR) signals, building a high-comfort hybrid BCI based on weak audio-visual evoked responses. This system coded 40 targets via 20 high-frequency visual stimulation frequencies and two auditory stimulation frequencies, improving the coding efficiency of BCI systems. Results showed that the hybrid system's averaged classification accuracy was (78.00 ± 12.18) %, and the information transfer rate (ITR) could reached 27.47 bits/min. This study offers new ideas for the design of hybrid BCI paradigm based on imperceptible stimulation.
Brain-Computer Interfaces ; Humans ; Evoked Potentials, Visual/physiology* ; Acoustic Stimulation ; Photic Stimulation ; Electroencephalography ; Evoked Potentials, Auditory/physiology* ; Adult

Objective To investigate the aberrant methylation and expression of growth arrest and DNA-damage-in-ducible 45 gamma (GADD45G) gene in gastric cardia adenocarcinoma (GCA). Methods Bisulfite conversion-methylation specific polymerase chain reaction method (BS-MSP) and immunohistochemistry method were used respectively to detect the methylation status and protein expression of GADD45G in 138 GCA tumor tissues and corresponding normal tissues. Re-sults The methylation status of GADD45G distal promoter (region 1) was not detected in GCA tumor tissues and corre-sponding normal tissues. For GADD45G region 2 and region 3, the BS-MSP results of region 3 were identical to that of re-gion 2. The methylation frequency of proximal promoter and exon 1 in GADD45G island 2 (region 2 and region 3) in GCA tu-mor tissues (49.3%, 68/138) was significantly increased compared to that in corresponding normal tissues (0, P＜0.01). The methylation status of this two sites in tumor tissues was associated with TNM stage of tumors (P＜0.05). The protein expres-sion of GADD45G in tumor tissues was significantly decreased than that in corresponding normal tissues (P ＜ 0.05),and threre was a significant negative correlation with methylation status of GADD45G proximal promoter and exon 1 (rs=-0.398). Conclusion The decreased expression of GADD45G by hypermethylation of proximal promoter exon 1 of the gene may play an important role in gastric cardia adenocarcinoma.