PNAS：社会因素影响对触摸的感知

6月4日，刊登在PNAS上的一篇文章中，科研人员发现了社会和触觉信息帮助人类大脑处理触觉，这可能解释了当一个人提供的肉体爱抚被认为是有吸引力的或是可憎的时候所引发的矛盾的感受。

Valeria Gazzola及其同事检测了18位健康的异性恋男性在女性研究参与者轻柔地抚摸他们的腿的时候的大脑活动。这些男性无法看到这些女性，但是认为抚摸者是有吸引力的女性或者是另一位男性。在实验期间让这些男性观看的录像加强了这类信念。

当这些男性认为他们被一位有吸引力的女性抚摸的时候，他们的大脑的初级体感皮层比当他们认为被一位没有吸引力的男性抚摸的时候更活跃，尽管事实上这种抚摸总是由同一人提供的。尽管初级体感皮层曾经被认为是客观地呈现了皮肤的触感，当前这些发现表明这种呈现受到了接受者对抚摸者的看法的影响。这组作者说，这些结果提示初级体感皮层没有此前认为得那样客观。（生物谷Bioon.com）

doi:10.1073/pnas.1113211109
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Primary somatosensory cortex discriminates affective significance in social touch

Valeria Gazzolaa,b,1, Michael L. Spezioc,d,1, Joset A. Etzela, Fulvia Castellie, Ralph Adolphsd,f,2, and Christian Keysersa,b,d,2

Another person’s caress is one of the most powerful of all emotional social signals. How much the primary somatosensory cortices (SIs) participate in processing the pleasantness of such social touch remains unclear. Although ample empirical evidence supports the role of the insula in affective processing of touch, here we argue that SI might be more involved in affective processing than previously thought by showing that the response in SI to a sensual caress is modified by the perceived sex of the caresser. In a functional MRI study, we manipulated the perceived affective quality of a caress independently of the sensory properties at the skin: heterosexual males believed they were sensually caressed by either a man or woman, although the caress was in fact invariantly delivered by a female blind to condition type. Independent analyses showed that SI encoded, and was modulated by, the visual sex of the caress, and that this effect is unlikely to originate from the insula. This suggests that current models may underestimate the role played by SI in the affective processing of social touch.