Zhao Weihua, Geng Yayuan, Luo Lizhu, Zhao Zhiying, Ma Xiaole, Xu Lei, Yao Shuxia, Kendrick Keith M
Key Laboratory for Neuroinformation, Center for Information in Medicine, School of Life Science and Technology, University of Electronic Science and Technology of ChinaChengdu, China.
Front Hum Neurosci. 2017 May 23;11:272. doi: 10.3389/fnhum.2017.00272. eCollection 2017.
The neuropeptide oxytocin (OXT) can influence self-processing and may help motivate us to value the attributes of others in a more self-like manner by reducing medial prefrontal cortex (mPFC) responses. We do not know however whether this OXT effect extends to possessions. We tend to place a higher monetary value on specific objects that belong to us compared to others, known as the "endowment effect". In two double-blind, between-subject placebo (PLC) controlled experiments in subjects from a collectivist culture, we investigated the influence of intranasal OXT on the endowment effect, with the second study incorporating functional magnetic resonance imaging (fMRI). In the task, subjects decided whether to buy or sell their own or others' (mother/father/classmate/stranger) possessions at various prices. Both experiments demonstrated an endowment effect in the self-owned condition which extended to close others (mother/father) and OXT increased this for self and all other-owned items. This OXT effect was associated with reduced activity in the ventral mPFC (vmPFC) in the self-owned condition but increased in the mother-condition. For the classmate- and stranger-owned conditions OXT increased activity in the dorsal mPFC (dmPFC). Changes in vmPFC activation were associated with the size of the endowment effect for self- and mother-owned items. Functional connectivity between the dmPFC and ventral striatum (VStr) was reduced by OXT in self- and mother-owned conditions and between vmPFC and precuneus in the self-condition. Overall our results show that OXT enhances the endowment effect for both self- and other-owned items in Chinese subjects. This effect is associated with reduced mPFC activation in the self-condition but enhanced activation in all other-conditions and involves differential actions on both dorsal and ventral regions as well as functional connectivity with brain reward and other self-processing regions. Overall our findings suggest that OXT increases the perceived value of both self- and other-owned items by acting on neural circuitry involved in self-processing and reward.
神经肽催产素（OXT）会影响自我认知加工，并且可能通过降低内侧前额叶皮质（mPFC）的反应，促使我们以更像看待自己的方式重视他人的特质。然而，我们尚不清楚这种催产素效应是否会延伸至对物品的认知。与他人的物品相比，我们往往会赋予属于自己的特定物品更高的货币价值，这就是所谓的“禀赋效应”。在针对来自集体主义文化的受试者进行的两项双盲、受试者间安慰剂（PLC）对照实验中，我们研究了鼻内给予催产素对禀赋效应的影响，第二项研究还纳入了功能磁共振成像（fMRI）。在任务中，受试者要决定是否以不同价格买卖自己或他人（母亲/父亲/同学/陌生人）的物品。两项实验均表明，在自有物品条件下存在禀赋效应，且这种效应延伸至关系亲密的他人（母亲/父亲），催产素增强了自我及所有他人物品的这种效应。这种催产素效应在自有物品条件下与腹侧mPFC（vmPFC）活动减少有关，但在母亲物品条件下活动增加。对于同学和陌生人的物品条件，催产素增加了背侧mPFC（dmPFC）的活动。vmPFC激活的变化与自我和母亲物品的禀赋效应大小相关。在自我和母亲物品条件下，催产素降低了dmPFC与腹侧纹状体（VStr）之间的功能连接，在自我条件下降低了vmPFC与楔前叶之间的功能连接。总体而言，我们的结果表明，催产素增强了中国受试者对自我和他人物品的禀赋效应。这种效应在自我条件下与mPFC激活减少有关，但在所有其他条件下激活增强，并且涉及对背侧和腹侧区域的不同作用以及与大脑奖赏和其他自我认知加工区域的功能连接。总体而言，我们的研究结果表明，催产素通过作用于参与自我认知加工和奖赏的神经回路，增加了自我和他人物品的感知价值。
