Abstract

We used near-infrared spectroscopy to separate tissue scattering changes from changes in cerebral oxy- and deoxyhemoglobin and the redox state of Cytochrome-c-oxidase during cortical spreading depression (CSD) in barbiturate anesthetized rats. A separate term for the transport scattering coefficient (µ_s’) was added in a modified Lambert-Beer equation where the differential pathlength factor (D_a) and its scattering equivalent (D_s) are included. During CSDs recorded through the skull of rats strong biphasic changes in µ_s’ of about ± 0.1 mm-1 were observed that spread with a velocity of about 5 mm/min. It is shown that the DC potential recorded on the skull has a strong correlation with the scattering properties. This was found during CSDs as well as during the period of the anoxic cell depolarisation after sacrificing the animal.

© 1998 Optical Society of America