An approach to neuroimaging in which lasers emit infrared light through the skull into the brain and light-detecting sensors record the light that returns. The absorption and reflection of the infrared light can indicate where in the upper brain regions oxygenated red blood cells are concentrated, thereby allowing inferences for those areas that are active during a given task. fNIRS has been tried experimentally in deception detection. See: Butta et al., 2015; Li et al, (2018); Tian et al. (2009).
