Fig. 7.

Representative NIR spectra collected from the cortex of one mouse. A. Spectra of the light source after calibration (I_ref). B. Light intensity (I_S) recorded from the cortex of the mouse during different F_iO₂ levels. Each line represents the average of all the spectra collected during the period of the corresponding O₂ challenge. C. Attenuation spectra of the mouse cortex calculated with $A=-\text{ln}\left(\frac{I_S}{I_{\mathit{\text{ref}}}}\right)$ . D. Second derivative of the attenuation spectra in (C). E. Second derivative of the attenuation spectra in (C) using the smoothing algorithm SAVGOL with the number of smoothing points = 15. F. Second derivative of the attenuation spectra in (C) using the smoothing algorithm SAVGOL with the number of smoothing points = 45.