Optical Imaging of the Motor Cortex in the Brain in Order to Determine the Direction of the Hand Movements Using Functional Near-Infrared Spectroscopy (fNIRS)

Abstract

<strong>Introduction</strong>: In recent years, optical imaging has attracted a lot of attention from scholars as a non- aggressive, efficient method for evaluating the activities of the motor cortex in the brain. Functional near-infrared spectroscopy (fNIRS (is a tool showing the hemodynamic changes in a cortical area of the brain according to optical principles. The present study has been designed to investigate and evaluate the cortical activities of the brain during the performance of hand motor tasks which we have a lot every day. <strong>Materials and Methods:</strong> In the present research, the activity of the motor cortex in the brain was investigated during the vertical and horizontal movements of the right hand. To carry out the purpose of this study, 6 healthy right-handed volunteers (25-40 years of age) were used. The required data were collected using a 48-channel fNIRS device compatible with MR (OxyMonfNIRS manufactured by Artinis) with two 763 and 845 nanometer wavelengths. 8 infrared transmitters and 8 infrared receivers, constituting 20 channels in all, were used for the purposes of the experiment. The distance between the transmitters and receivers was 30 mm and a sampling frequency of 10 Hz was also chosen. The obtained data were processed and analyzed using the NIRS_SPM toolbox. <strong>Results:</strong> The results demonstrated that the hemodynamic signal intensity in the motor cortex in the brain during the performance of motor tasks was significantly increased (p≤0.05) in comparison to the state when body is resting. The study findings showed that the activation map for the activities related to the direction of the movement's performance in the motor cortex in the brain are spatially separate and distinguishable, and the highest level of activity was recorded in the primary motor cortex (M1) area. <strong>Conclusion:</strong> The results of this research demonstrated that it is possible to distinguish the various directions of hand movements using Functional near-infrared spectroscopy (fNIRS) signals. The existence of direction-dependent activation in the motor cortex in the brain helps develop the idea that this part of the brain cortex not only controls the movements of the various parts of the body, but also has a role in processing complicated information such as distinguishing between the various directions of hand movements. The results obtained from this research may also be useful to further studies on movement control