Asumbisa Kadjita, Peyrache Adrien, Trenholm Stuart
Montreal Neurological Institute, McGill University, Montreal, Canada.
Nat Commun. 2025 Apr 14;16(1):3545. doi: 10.1038/s41467-025-58847-7.
Stereo olfaction, the difference in odor concentration between the two nostrils, has been shown to affect a variety of animal behaviors, including olfactory search. However, it is unknown whether stereo olfaction can enable the formation of allocentric spatial representations. Here, recording from head direction (HD) cells in the anterior dorsal nucleus of the thalamus in blind mice-a model system for studying olfaction-dependent allocentric spatial representations-we find that inhibiting stereo olfaction, by blocking olfactory processing in one nostril or merging the airflow going to both nostrils, drastically impairs head direction coding. To assess the behavioral impact of impaired HD cell tuning caused by loss of stereo olfaction, we developed a closed-loop head direction preference assay, in which a mouse received medial forebrain bundle reward stimulation upon orientating its head in a specific direction. We find that inhibiting stereo olfaction significantly impairs performance in the HD preference assay. These results reveal that stereo olfaction is required for mice to use smell to form a stable allocentric spatial representation of head direction.
立体嗅觉，即两个鼻孔之间气味浓度的差异，已被证明会影响包括嗅觉搜索在内的多种动物行为。然而，立体嗅觉是否能够促成以自我为中心的空间表征的形成尚不清楚。在这里，我们从盲鼠丘脑前背核的头部方向（HD）细胞进行记录——这是一种用于研究依赖嗅觉的以自我为中心的空间表征的模型系统——我们发现，通过阻断一个鼻孔的嗅觉处理或合并流向两个鼻孔的气流来抑制立体嗅觉，会严重损害头部方向编码。为了评估因立体嗅觉丧失导致的HD细胞调谐受损对行为的影响，我们开发了一种闭环头部方向偏好测定法，在该测定法中，小鼠在将头部定向到特定方向时会受到内侧前脑束奖励刺激。我们发现，抑制立体嗅觉会显著损害HD偏好测定中的表现。这些结果表明，小鼠需要立体嗅觉才能利用嗅觉形成稳定的以自我为中心的头部方向空间表征。
