Odor landscapes contain complex blends of molecules that each activate unique, overlapping populations of olfactory sensory neurons (OSNs). Despite the presence of hundreds of OSN subtypes in many animals, the overlapping nature of odor inputs may lead to saturation of neural responses at the early stages of stimulus encoding. Information loss due to saturation could be mitigated by normalizing mechanisms such as antagonism at the level of receptor-ligand interactions, whose existence and prevalence remains uncertain. By imaging OSN axon terminals in olfactory bulb glomeruli as well as OSN cell bodies within the olfactory epithelium in freely breathing mice, we find widespread antagonistic interactions in binary odor mixtures. In complex mixtures of up to 12 odorants, antagonistic interactions are stronger and more prevalent with increasing mixture complexity. Therefore, antagonism is a common feature of odor mixture encoding in OSNs and helps in normalizing activity to reduce saturation and increase information transfer.

气味景观包含复杂的分子混合物，每种分子都会激活独特的、重叠的嗅觉感觉神经元 (OSN) 群体。尽管许多动物体内存在数百种 OSN 亚型，但气味输入的重叠性质可能会导致刺激编码早期阶段的神经反应饱和。饱和导致的信息丢失可以通过规范化机制来减轻，例如受体-配体相互作用水平上的拮抗作用，但其存在和普遍性仍不确定。通过对自由呼吸小鼠嗅球肾小球中的 OSN 轴突末端以及嗅上皮内的 OSN 细胞体进行成像，我们发现二元气味混合物中存在广泛的拮抗相互作用。在多达 12 种气味剂的复杂混合物中，随着混合物复杂性的增加，拮抗相互作用会更强、更普遍。因此，拮抗作用是 OSN 中气味混合物编码的一个共同特征，有助于使活动正常化，以降低饱和度并增加信息传递。