Orexin cells efficiently decode blood glucose dynamics to drive adaptive behavior

Blood glucose variability shapes human brain performance and diverse clinical outcomes. However, it remains poorly understood how blood glucose fluctuations are decoded by genetically-defined neurons to change brain activity and behavior. Recent breakthroughs in genetics and clinical diagnostics identified hypothalamic hypocretin/orexin neurons (HONs) as core determinants of brain activity and adaptive behavior across mammals. Here we show that low-frequency HON population waves are tuned for transmitting information about minute-to-minute temporal features of blood glucose, thus rapidly converting its variability into brain state of behaving mice. Contrary to current theories envisioning glucose-proportional neural responses, the HONs response tracked blood glucose gradients, thus generating efficient neural adaptations in anticipation of maximal glucose deviations. Resolving this population response at the single cell level with volumetric multiphoton imaging furthermore revealed glucose-excited and glucose-inhibited HONs, distinctly coupled to body movements in the high-frequency domain. Finally, HON-selective opotogenetics and cell ablation demonstrated that HONs are critical for linking glucose to adaptive behavior. These results provide an insight into how behaviorally influential hypothalamic networks interpret blood glucose variability. This may inform future metrics for efficient prediction of glycemic states in health and disease.