Fig. 1.

Study design. Following 30 days of acclimatization, male Long Evans rats were randomly separated into 4 groups: group 1, MW + decapitation, in which rats were subjected to head-focused microwave fixation (13.5 kW for 1.6 s) prior to dissection (no ischemia; n = 8); group 2, CO₂ + MW + decapitation, in which rats were subjected to CO₂-induced asphyxiation for 2 min immediately followed by head-focused microwave fixation prior to dissection (n = 7); group 3, CO₂ + decapitation + MW, in which rats were subjected to CO₂-induced asphyxiation for 2 min, decapitated (and the decapitated heads left on the bench for an average of 6.38 min), and then subjected to microwave fixation prior to dissection (n = 8); and group 4, CO₂ + decapitation, in which rats were subjected to CO₂-induced asphyxiation for 2 min and then dissection (n = 8). The dissection time of group 3 (6.4 min) was matched to the dissection time of group 4 (6.6 min), which did not receive head-focused microwave irradiation. All brains were flash-frozen in liquid nitrogen after dissection. MW, microwave.