, alfaxalone/alfadolone, ketamine, and medetomidine delivered intravenously using a programmable infusion pump. Anesthetic induction for each agent was tracked using five behavioral endpoints: loss of righting reflex, criterion for anesthesia (score of 11 or higher), criterion for surgical anesthesia (score of 14 or higher), antinociception (loss of pinch response), and deep surgical anesthesia (score of 16 , responsiveness to the neurosteroids alfaxalone and alfadolone remained unchanged compared with baseline (94 ± 24%; P = 0.519; 6 lesioned rats and 18 controls) and with ketamine increased slightly (90 ± 11%; P = 0.039; 6 lesioned rats and 19 controls). The non-GABAergic anesthetic medetomidine did not induce criterion anesthesia even at the maximal dose tested. The dose to reach the maximal anesthesia score