Department of Otorhinolaryngology, Smell and Taste Clinic, TU Dresden, Dresden, Germany.
Department of Clinical Psychology, Friedrich Schiller University, Jena, Germany.
Sci Rep. 2023 Jun 21;13(1):10072. doi: 10.1038/s41598-023-36783-0.
Depression is associated with reduced olfactory function. This relationship is assumed to be based on either a reduced olfactory bulb volume or diminished functioning of higher cortical areas. As previous results are controversial, we aimed to re-evaluate central olfactory processing in depression. We recorded the BOLD signal of 21 patients with Major Depressive Disorder and 21 age and gender matched healthy controls during odor presentation. In addition, we measured the individual olfactory bulb volume, tested odor identification and odor threshold, and asked for hedonic odor perception. In both groups, odor presentation led to a pronounced activation of primary olfactory areas. However, secondary olfactory areas were significantly less activated in depressed individuals. The two groups did not differ in olfactory bulb volume. Our results point towards altered olfactory processing in patients in those regions that relate to sensory integration and attention allocation. Difficulties in cognitive processing could impact olfactory function in depression. We are therefore in favor of a top-down mechanism originating in higher cortical areas explaining parts of the relation between depression and olfaction.
抑郁与嗅觉功能减退有关。这种关系假定基于嗅球体积减小或更高皮质区域功能下降。由于先前的结果存在争议，我们旨在重新评估抑郁患者的中枢嗅觉处理。我们在气味呈现期间记录了 21 名重度抑郁症患者和 21 名年龄和性别匹配的健康对照者的 BOLD 信号。此外，我们测量了个体的嗅球体积，测试了气味识别和气味阈值，并询问了愉悦的气味感知。在两组中，气味呈现都导致了初级嗅觉区域的明显激活。然而，在抑郁个体中，二级嗅觉区域的激活明显减少。两组在嗅球体积上没有差异。我们的结果表明，在与感觉整合和注意力分配相关的区域，患者的嗅觉处理发生了改变。认知处理困难可能会影响抑郁患者的嗅觉功能。因此，我们倾向于认为，源自更高皮质区域的自上而下的机制可以解释抑郁和嗅觉之间部分关系。
