Hedonic perception deeply changes with aging, significantly impacting health and quality of life in elderly. In young adult mice, an odor hedonic signature is represented along the antero-posterior axis of olfactory bulb, and transferred to the olfactory tubercle and ventral tegmental area, promoting approach behavior. Here, we show that while the perception of unattractive odorants was unchanged in older mice (22 months), the appreciation of some but not all attractive odorants declined. Neural activity in the olfactory bulb and tubercle of older mice was consistently altered when attraction to pleasant odorants was impaired while maintained when the odorants kept their attractivity. Finally, in a self-stimulation paradigm, optogenetic stimulation of the olfactory bulb remained rewarding in older mice even without ventral tegmental area’s response to the stimulation. Aging degrades behavioral and neural responses to some pleasant odorants but rewarding properties of olfactory bulb stimulation persisted, providing new insights into developing novel olfactory training strategies to elicit motivation even when the dopaminergic system is altered as observed in normal and/or neurodegenerative aging.

中文翻译：

---

小鼠对有吸引力气味的感知和编码与年龄相关的差异

享乐知觉随着年龄的增长而发生深刻变化，显着影响老年人的健康和生活质量。在年轻的成年小鼠中，气味享乐特征沿着嗅球的前后轴呈现，并转移到嗅结节和腹侧被盖区，促进接近行为。在这里，我们发现，虽然老年小鼠（22 个月）对不吸引人的气味的感知没有变化，但对一些但并非全部有吸引力的气味的感知有所下降。当对令人愉快的气味的吸引力受损时，年长小鼠嗅球和嗅结节的神经活动会持续改变，而当气味保持吸引力时则保持不变。最后，在自我刺激范例中，即使腹侧被盖区对刺激没有反应，嗅球的光遗传学刺激对老年小鼠仍然有益。衰老会降低对某些令人愉悦的气味的行为和神经反应，但嗅球刺激的有益特性仍然存在，这为开发新颖的嗅觉训练策略以激发动机提供了新的见解，即使多巴胺能系统发生了如正常和/或神经退行性衰老中观察到的变化。