A wearable fiber-free optical sensor for continuous monitoring of cerebral blood flow in freely moving mice

We present an innovative, wearable, fiber-free, near-infrared diffuse speckle contrast flowmetry (DSCF) probe that is fixed on the skull for continuous monitoring of cerebral blood flow (CBF) variations in mice during anesthesia, awake, and freely behaving. Results show a small surge when the animal waked up, a mild decrease after the isoflurane washed off, a 37 ± 9% increase during 10%CO2 inhalation (n = 3), and mild elevations during grooming and walking. These CBF variations are consistent with clinical observations when recovery from anesthesia and impacts by isoflurane, hypercapnia (CO2), and activity-induced cortical excitations.