Anesthesia and monitoring

Before microsurgery and imaging experiments, anesthesia was induced with 4% isoflurane in N₂O:O₂ (3:2). Anesthesia was maintained with 2–2.5% isoflurane during microsurgeries, and 1.5% during imaging sessions, while breathing was always unassisted. Rats were restrained in a stereotaxic frame during uUS imaging or in an MR-compatible stereotaxic cradle during MRI experiments. Rats received ophthalmic eye cream (Duratears™ Z, Alcon, Switzerland) before microsurgery and imaging. Animals also received 10 mg/kg subcutaneous lidocaine (Xylocaine 5%, AstraZeneca, Sweden) under the scalp prior to craniotomy, and in the throat area prior to MCAO microsurgery. When anesthetized, body temperature was maintained at 37 ± 0.5 °C by a feedback-controlled heating pad. Blood oxygen saturation and heart rate were continuously monitored throughout surgeries and imaging sessions. To maintain body hydration, 0.9% NaCl was injected after microsurgery and after every hour of imaging to guard hydration status.