Application of functional near-infrared imaging for conflict monitoring: a preliminary study in 28 adults

Abstract

Objective To study the difference of cerebral blood oxygen response of subjects with different reaction speed under conflict task with the aid of functional near-infrared spectroscopy (fNIRS) in order to explore the neural mechanism of conflict monitoring. Methods Twenty-eight healthy students from our university were recruited as the subjects. They were 16 males and 12 females, at an age of 17~20 (18.79±0.55) years. The changes of blood oxygen concentration in the brain of these subjects during Stroop task were collected by fNIRS. According to their response time in Stroop task, they were assigned into fast group and slow group, with 14 students in each group. The data were analyzed by nirsLAB software to compare the changes of the relative concentration of oxygenated hemoglobin (HbO2) and the relative concentration of deoxygenated hemoglobin (Hb) between the 2 groups, and the correlation between the behavioral indexes and the changes of cerebral blood oxygen concentration was analyzed. Results Stroop task mainly activated bilateral dorsolateral prefrontal cortex (DLPFC) and frontal polar region. Compared with the slow group, the relative concentration of Hb was decreased significantly in the fast group under Stroop task, mainly located in the left DLPFC and frontal polar region (P < 0.05). Also, the relative concentration of Hb in Ch4 channel was positively correlated with the reaction time(r=0.422 3, P=0.025 2). Conclusion Our results verify the core role of DLPFC in conflict monitoring, and find that the relative change of Hb concentration in the left frontal polar region can be regarded as an important indicator to reflect the conflict monitoring of the subjects.

Keywords

• functional near-infrared spectroscopy
• conflict monitoring
• stroop task
• blood oxygen concentration