fNIRS based color detection from human visual cortex

In this study, functional near-infrared spectroscopy (fNIRS) is used to measure the relative hemodynamic response changes in the visual cortex for 10 subjects (aged 22~34 years old), while they watch red, green, and blue (RGB) colors on a projection screen. The concentration changes of oxygenated and deoxygenated hemoglobin (HbO and HbR) are measured in 30 channels (i.e., 15 sources and 15 detectors combination). The data recorded using the RGB color stimuli show a significant increase in the HbO in the visual cortex. It is found that the HbO changes are more active in the left side of the human visual cortex than the right side. It was able to distinguish red, green and blue colors using the fNIRS technology. The results suggest that investigating the human visual cortex by monitoring the hemodynamic response patterns with fNIRS is a viable method in understanding the human brain.