Lucas Molly V, Anderson Laura C, Bolling Danielle Z, Pelphrey Kevin A, Kaiser Martha D
Yale Child Study Center, Yale University, New Haven, CT 06520, USA.
Department of Psychology, University of Maryland, College Park, MD 20742, USA.
Cereb Cortex. 2015 Sep;25(9):2623-30. doi: 10.1093/cercor/bhu061. Epub 2014 Apr 3.
This functional magnetic resonance imaging (fMRI) study examined experiencing and imagining gentle arm and palm touch to determine whether these processes activate overlapping or distinct brain regions. Although past research shows brain responses to experiencing and viewing touch, this study investigates neural processing of touch absent of visual stimulation. C-tactile (CT) nerves, present in hairy skin, respond specifically to caress-like touch. CT-targeted touch activates "social brain" regions including insula, right posterior superior temporal sulcus, amygdala, temporal poles, and orbitofrontal cortex ( McGlone et al. 2012). We addressed whether activations reflect sensory input-driven mechanisms, cognitive-based mechanisms, or both. We identified a functional dissociation between insula regions. Posterior insula responded during experienced touch. Anterior insula responded during both experienced and imagined touch. To isolate stimulus-independent mechanisms recruited during physical experience of CT-targeted touch, we identified regions active to experiencing and imagining such touch. These included amygdala and temporal pole. We posit that the dissociation of insula function suggests posterior and anterior insula involvement in distinct yet interacting processes: coding physical stimulation and affective interpretation of touch. Regions active during experiencing and imagining CT-targeted touch are associated with social processes indicating that imagining touch conjures affective aspects of experiencing such touch.
这项功能磁共振成像（fMRI）研究检测了感受和想象轻柔的手臂及手掌触摸，以确定这些过程是否会激活重叠或不同的脑区。尽管过去的研究显示了大脑对感受和观看触摸的反应，但本研究调查了在没有视觉刺激情况下触摸的神经处理过程。存在于有毛皮肤中的C触觉（CT）神经对类似爱抚的触摸有特异性反应。针对CT的触摸会激活包括脑岛、右后颞上沟、杏仁核、颞极和眶额皮质在内的“社交脑”区域（McGlone等人，2012年）。我们探讨了这些激活是反映感觉输入驱动机制、基于认知的机制，还是两者兼而有之。我们确定了脑岛区域之间的功能分离。后脑岛在感受触摸时做出反应。前脑岛在感受触摸和想象触摸时均做出反应。为了分离在针对CT的触摸的身体体验过程中招募的与刺激无关的机制，我们确定了对感受和想象这种触摸有反应的区域。这些区域包括杏仁核和颞极。我们认为，脑岛功能的分离表明后脑岛和前脑岛参与了不同但相互作用的过程：对物理刺激进行编码以及对触摸进行情感解读。在感受和想象针对CT的触摸时活跃的区域与社交过程相关，这表明想象触摸会唤起感受这种触摸的情感方面。
