Real-time fNIRS signal acquisition system: Compatible with TMS

Functional near-infrared spectroscopy (fNIRS) is a non-invasive neural imaging tool which provides information of the oxidative metabolism in the brain by using diffused near-infrared light. Transcranial magnetic stimulation (TMS) is a physical stimulus, which can directly interfere with the neuron activity. The combination of fNIRS with TMS enables researchers to directly study the dynamic causality between different brain regions and the network of the particular brain region. In this paper, we design a dual channels real-time fNIRS system that can work during TMS stimulus. This system consists of hardware part and software part, to realize the blood oxygen signal acquisition and analog-to-digital conversion. The hardware part includes optical fiber probe and acquisition card of the national instruments. Software part is based on the LabVIEW, to develop the PC software, to implement the control of the system and the real-time display and storage of signals.