Challenges in inferring breathing rhythms from olfactory bulb local field potentials.

Abstract

Odors convey useful navigational and episodic information, yet much of the chemical world remains inaccessible without active sampling through sniffing. Respiratory cycles control odor dynamics within the nose, so understanding olfactory bulb (OB) neural dynamics requires accurate respiratory measurements. While respiratory behavior can be measured directly with a variety of chronic methods, these methods are invasive, and none are perfectly robust. OB local field potentials (LFPs) have long been known to couple with respiration. Here, we investigated whether the precise timing and frequency of respiration can be inferred from OB LFPs. Our results replicate previous findings that OB LFPs across multiple frequency bands align with respiratory cycles. Further, these OB rhythms are locked to time in the respiratory cycle, and not phase. In addition, we show that 2 to 12 Hz LFP oscillations effectively track sniffing rate. However, a monotonic relationship between LFP-respiratory delay and sniffing rate, which varies across animals, renders the recovery of precise respiratory events challenging. This work underscores the complex and individualized relationship between rodent respiration and OB LFPs, contributing to our understanding of how respiration controls olfaction.