School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
Fuzhi Cao
School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
Wen Li
School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
Wenli Wang
School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
Weinan Xu
School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
Chunhui Wang
School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
Min Xiang
Research Institute of Frontier Science, Beihang University, Beijing 100191, China; Hangzhou Innovation Institute, Beihang University, Hangzhou 100191, China
Yang Gao
Hangzhou Innovation Institute, Beihang University, Hangzhou 100191, China; Beijing Academy of Quantum Information Sciences, Beijing 100193, China
Binbin Sui
Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China
Aimin Liang
Beijing Children’s Hospital, Capital Medical University, Beijing 100045, China
Xiaolin Ning
Research Institute of Frontier Science, Beihang University, Beijing 100191, China; Hangzhou Innovation Institute, Beihang University, Hangzhou 100191, China; Corresponding author
Summary: In recent years, optically pumped magnetometer (OPM)-based magnetoencephalography (MEG) has shown potential for analyzing brain activity. It has a flexible sensor configuration and comparable sensitivity to conventional SQUID-MEG. We constructed a 32-channel OPM-MEG system and used it to measure cortical responses to median and ulnar nerve stimulations. Traditional magnetic source imaging methods tend to blur the spatial extent of sources. Accurate estimation of the spatial size of the source is important for studying the organization of brain somatotopy and for pre-surgical functional mapping. We proposed a new method called variational free energy-based spatial smoothing estimation (FESSE) to enhance the accuracy of mapping somatosensory cortex responses. A series of computer simulations based on the OPM-MEG showed better performance than the three types of competing methods under different levels of signal-to-noise ratios, source patch sizes, and co-registration errors. FESSE was then applied to the source imaging of the OPM-MEG experimental data.
