Abstract
The human brain function measurement by light that applies near-infrared spectroscopy (NIRS) has
accomplished rapid development in these 30 years. We developed the optical topography (OT) method
to make an image of the brain activity by the multipoint measurement simultaneously based on NIRS
(1995). OT has several features. 1) It can measure brain activity in the daily life naturally. 2) It can
measure the brain activity only by putting on the optical fiber cap. 3) It can measure the neonatal brain
function because light level is safe for the baby brain. 4) The measurement signal can be used to know
the autonomic nervous system. We have achieved the application to neurosurgery; the diagnosis of the
epileptic focus and the dominant hemisphere for language. Moreover, we have found neonatal brain
function concerning the language and sleep. Now, everyone can measure the brain function anytime and
anywhere. It is expected to become an effective tool to the approach of a different research field and a
new brain imaging. We need understanding of the meaning of the measurem
