In vivo and noninvasive measurement of a songbird head's optical properties.

By assessing the cerebral blood volume and the hemoglobin oxygen saturation level, near-infrared spectroscopy (NIRS) probes brain oxygenation, which reflects cerebral activity. To develop a noninvasive method monitoring the brain of a songbird, we use an original NIRS device, i.e., a white laser coupled with an ultrafast spectrotemporal detector of optical signals without wavelength scanning. We perform in vivo measurements of the absorption coefficient and the reduced scattering coefficient of the caudal nidopallium area of the head of a songbird (the zebra finch).