A projection atlas of excitatory and inhibitory inputs to the preBötzinger complex: substrates for multimodal...

Breathing is an essential motor behavior that originates from the activity of rhythm-generating neurons in the preBötzinger complex (preBötC). Although the properties of preBötC neurons are sufficient for rhythmogenesis, their activity is continually shaped by long-range inputs that convey homeostatic, emotional, volitional, and behavioral influences. Here, we provide a systematic survey of projections from excitatory (glutamatergic) and inhibitory (GABAergic) neurons across the mouse brain that target the preBötC. Using a dual recombinase-dependent retrograde tracing approach, we compile an atlas of afferent regions, highlighting the breadth of excitatory and inhibitory inputs that converge on this critical brainstem area. This atlas underscores the preBötC as a nexus where multimodal signals are integrated to regulate rhythm generation and patterning. Rather than a self-contained oscillator, the preBötC is a hub whose function is tuned by diverse long-range excitatory and inhibitory influences. By defining the anatomical substrates of this input, we lay a foundation for dissecting the functional roles of higher-order brain regions in shaping breathing across physiological, behavioral, and pathological contexts.NEW & NOTEWORTHY The rhythm for each breath is generated by a specialized brainstem region called the preBötzinger complex. Many brain areas influence this region, but the sources of these inputs-and whether they excite or inhibit breathing-have not been systematically mapped. Here, we present an atlas identifying where excitatory and inhibitory signals to the preBötzinger complex arise across the mouse brain, providing a framework for understanding how breathing is shaped by sensory signals, behavior, and brain state.