Influence of odors on pleasant touch perception

该项目旨在研究气味对愉悦触觉的影响。愉快的触摸是一种非常基本的感觉，对所有类型的社会关系都有影响，特别是对亲密伴侣和孩子。编码愉悦触觉的感觉神经元被称为C-触觉传入。正如显微神经学研究显示的那样，这些神经元位于人类多毛的皮肤上，对无害的机械刺激做出反应，并通过愉悦的触摸最强烈地激活。C-触觉编码的触觉即使在长时间的刺激下也非常健壮。我想确定气味是如何调节触觉愉悦的感觉的。众所周知，气味是强大的情感诱导者。它们很容易影响情绪，可以携带关于他人情绪状态的信息，在择偶方面发挥着重要作用。因此，我假设气味会影响愉悦触摸的知觉。为了检验这一点，我们进行了两项研究：一项是心理物理实验，一项是fMRI研究。在这两项研究中，参与者都被一个带有C-触觉相关触摸的机器人刺激，在刺激之前有三种不同的气味：恶心的气味、愉快的气味和出于控制目的的中性气味。在心理物理实验中，参与者被要求对感觉到的触摸快感进行评级，而在功能磁共振研究中，编码气味和触摸相互作用的大脑区域的激活被分析。因此，该项目将导致对愉悦触摸和嗅觉的感觉整合的理解。此外，我希望它为更好地理解心身疾病打开了大门，这些疾病伴随着愉悦触觉的障碍，如强迫症、进食障碍或自闭症。

The project aims to study the influence of odors on pleasant touch perception. Pleasant touch is a very basic sensation with implications for all kind of social relationships, especially to intimate partners and to children. The sensory neurons that code pleasant touch perception are called C-tactile afferents. Those neurons are located in human hairy skin and respond to innocuous, mechanical stimuli and are most vigorously activated by pleasant touch, as microneurography studies could show. C-tactile coded touch perception is very robust even for long times of stimulation. I want to determine how the perception of touch as being pleasant can be modulated by odors. It is known that odors are powerful emotion elicitors. They are easily able to influence mood, can carry information about the emotional state of others and play an important role in mate choice. Therefore, I hypothesize that odors influence the perception of pleasant touch.Two studies are carried out to examine this: a psychophysical experiment and an fMRI Study. In both studies the participants are stimulated by a robot with C-tactile relevant touch, which is preceded by three different kinds of odors: a disgusting one; a pleasant one and a neutral one for control purpose. For the psychophysical experiment the participants are asked to rate the perceived pleasantness of the touch, for the fMRI study the activation of brain areas coding the interaction of odor and touch is analyzed. In result, the project will lead to an understanding of sensory integration of pleasant touch and olfaction. Furthermore, I hope it opens the door to a better understanding of psychosomatic diseases that go along with disturbance in pleasant touch perception, like obsessive compulsive disorder, eating disorder or autism.