Kollndorfer K, Jakab A, Mueller C A, Trattnig S, Schöpf V
Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria; Department of Pediatric and Adolescent Medicine, Medical University of Vienna, Austria.
Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Austria.
Neuroscience. 2015 Dec 3;310:589-99. doi: 10.1016/j.neuroscience.2015.09.045. Epub 2015 Sep 28.
The effects of sensory loss on central processing in various sensory systems have already been described. The olfactory system holds the special ability to be activated by a sensorimotor act, without the presentation of an odor. In this study, we investigated brain changes related to chronic peripheral smell loss. We included 11 anosmic patients (eight female, three male; mean age, 43.5 years) with smell loss after an infection of the upper respiratory tract (mean disease duration, 4.64 years) and 14 healthy controls (seven female, seven male; mean age, 30.1 years) in a functional magnetic resonance imaging experiment with a sniffing paradigm. Data were analyzed using group-independent component analysis and functional connectivity analysis. Our results revealed a spatially intact olfactory network in patients, whereas major aberrations due to peripheral loss were observed in functional connectivity through a variety of distributed brain areas. This is the first study to show the re-organization caused by the lack of peripheral input. The results of this study indicate that anosmic patients hold the ability to activate an olfaction-related functional network through the sensorimotor component of odor-perception (sniffing). The areas involved were not different from those that emerged in healthy controls. However, functional connectivity appears to be different between the two groups, with a decrease in functional connectivity in the brain in patients with chronic peripheral sensory loss. We can further conclude that the loss of the sense of smell may induce far-reaching effects in the whole brain, which lead to compensatory mechanisms from other sensory systems due to the close interconnectivity of the olfactory system with other functional networks.
各种感觉系统中感觉丧失对中枢处理的影响已有描述。嗅觉系统具有一种特殊能力，即能被感觉运动行为激活，而无需呈现气味。在本研究中，我们调查了与慢性外周嗅觉丧失相关的大脑变化。我们纳入了11名嗅觉丧失患者（8名女性，3名男性；平均年龄43.5岁），他们在上呼吸道感染后出现嗅觉丧失（平均病程4.64年），以及14名健康对照者（7名女性，7名男性；平均年龄30.1岁），进行了一项采用嗅吸范式的功能磁共振成像实验。数据使用独立成分分析和功能连接分析进行分析。我们的结果显示患者的嗅觉网络在空间上是完整的，而在外周丧失导致的功能连接方面，通过各种分布的脑区观察到了主要异常。这是第一项显示外周输入缺失导致重组的研究。本研究结果表明，嗅觉丧失患者具有通过气味感知的感觉运动成分（嗅吸）激活嗅觉相关功能网络的能力。所涉及的区域与健康对照者中出现的区域并无不同。然而，两组之间的功能连接似乎有所不同，慢性外周感觉丧失患者大脑中的功能连接有所减少。我们可以进一步得出结论，嗅觉丧失可能在全脑诱发深远影响，由于嗅觉系统与其他功能网络紧密相连，这会导致其他感觉系统产生代偿机制。
