Figure 1.

Transformation from ischaemia intolerance to ischaemia tolerance in brainstem circuit function. (a) Example motor nerve recordings of output from the brainstem respiratory network before (top) and after (bottom) 30 days in a simulated overwintering environment (hibernation). The activity of this network is generated by a group of rhythm-generating neurons (RG) that activate motor neurons (black oval) to drive lung ventilation. After hibernation, motor circuit function gains the ability to operate for dramatically longer without oxygen and glucose delivery. (b) Metabolic enzymes assessed in this study are indicated in bold, with the gene name italicized. Small arrows indicate enzymatic steps not assessed in this study. (Online version in colour.)