请教严老师:单样本t检验为什么要用explicit mask?

严老师,数据预处理完后为什么要做单样本t检验,同时为什么要用explicit mask?一头雾水

建议多参阅一些文献,比如
Wang, Z., Yan, C., Zhao, C., Qi, Z., Zhou, W., Lu, J., He, Y., Li, K., 2011. Spatial patterns of intrinsic brain activity in mild cognitive impairment and alzheimer's disease: A resting-state functional MRI study. Hum Brain Mapp 32, 1720-1740.