实验目的是在N-back任务中利用功能性近红外光谱（fNIRS）进行脑力负荷的分级和测量研究。对18名被试者进行了图片N-back工作记忆任务，利用fNIRS采集了被试者大脑皮层前额叶的血氧变化，同时记录了绩效与主观问卷数据。结果发现不同难度任务下绩效结果、主观问卷结果及fNIRS参数均有显著差异；背外侧前额叶区（DLPFC）对fNIRS的响应比较敏感；利用支持向量机（SVM）可以较为准确地识别4个难度N-back任务的脑力负荷； SVM判决值的一种变换形式能够作为评估和预测脑力负荷的指标。

The objective is to use functional near-infrared spectroscopy (fNIRS) to classify and measure mental workload in n-back tasks. Prefrontal cortex (PFC) responses were monitored with fNIRS while 18 subjects completed n-back tasks, performance and NASA-TLX scales were also recorded. It was found that there was significant difference in performance, subjective scores, and fNIRS data under different difficulty tasks; dorsolateral prefrontal cortex (DLPFC) is more sensitive to fNIRS in PFC; using support vector machine (SVM) could realize accurate classification of 4 mental workload levels; SVM decision values could assess and predict mental workload effectively.