Neuro-imaging methods are considered to important ways to investigate infants' brain function and development. Especially, LAIRS (near-infrared spectroscopy) is the most attractive method for infant studies among other imaging methods, because of their non-invasiveness, low-restrictiveness and portability. However, there are still some issues: First, it is difficult to localize activated regions by LAIRS alone. Second, there is little consensus in the method of analyzing LAIRS data. In this report, we discuss these utilities and limitations of current LAIRS technique in more detail and emphasize that LAIRS study is still in a phase of growth toward enhancement of their knowledge-base.