Introduction

Brain activation in response to olfactory stimuli has been studied using functional magnetic resonance imaging (fMRI), but there is little knowledge about processing repeated olfactory information which is usual in daily life.

Methods

This fMRI study was designed to investigate brain response to repeated odorant stimulation with positive and negative valences in 12 healthy right-handed volunteers. There was a 25-min rest interval between two fMRI runs with identical stimulation paradigms with two odors, as phenylethyl alcohol (PEA) and isovaleric acid (IVA), and the two odors were released alternately.

Results

There was a similar activation pattern in regions of primary and secondary olfactory cortex induced by odors of both valences, especially by negative odor. Weakened activation of the brain is responsive to repeated both pleasant and unpleasant smell. Nevertheless, the repeated unpleasant odor has a more intimate relationship with the piriform cortex, amygdala, and hippocampus.

Conclusion

We conclude that asymmetric brain activation in response to repeated odorant stimulation depended on valences and that the unpleasant odor can evoke more negative emotion and profound memory.

Implications

We explore the central processing about repeated olfactory information applied fMRI for the first time, revealing asymmetric brain activation in response to repeated odors of pleasantness and unpleasantness.

中文翻译：

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对反复的愉快和不愉快气味响应的不同大脑激活

介绍

已经使用功能磁共振成像（fMRI）研究了响应嗅觉刺激的大脑激活，但是对处理日常生活中常见的重复嗅觉信息知之甚少。

方法

这项功能磁共振成像研究旨在调查12名健康惯用右手志愿者对重复加味刺激的大脑反应的阳性和阴性价。两次功能磁共振成像运行之间有25分钟的休息间隔，具有相同的刺激范式，并带有两种气味，如苯乙醇（PEA）和异戊酸（IVA），并且两种气味交替释放。

结果

在两种价态的气味，尤其是由负气味引起的初级和次级嗅觉皮层区域中，存在类似的激活模式。脑部减弱的激活是对反复出现的愉快和难闻气味的反应。然而，反复难闻的气味与梨状皮层，杏仁核和海马体有着更密切的关系。

结论

我们得出的结论是，响应于重复的气味刺激，大脑的不对称激活取决于化合价，难闻的气味会唤起更多的负面情绪和深刻的记忆。

含义

我们首次探索了应用fMRI进行重复嗅觉信息的中央处理，揭示了响应于愉悦和不愉快的反复气味的不对称大脑激活。