Porciello Giuseppina, Crostella Filippo, Liuzza Marco Tullio, Valentini Elia, Aglioti Salvatore Maria
Department of Psychology, "Sapienza", University of Rome, Via dei Marsi 78, I-00185 Rome, Italy; IRCCS, Fondazione Santa Lucia, Via Ardeatina 306, I-00179 Rome, Italy.
Department of Psychology, "Sapienza", University of Rome, Via dei Marsi 78, I-00185 Rome, Italy.
Neuropsychologia. 2014 Jul;59:148-56. doi: 10.1016/j.neuropsychologia.2014.04.017. Epub 2014 May 9.
In highly social groups like human and non-human primates, gaze and pointing cues are fundamentally important for directing the attention of conspecifics. Although neuroimaging studies indicate that shifts of attention triggered by observation of social cues activate the onlookers׳ fronto-parietal cortices, information on whether these regions play a causative role in orienting and re-orienting of social attention is lacking. To advance our understanding of this, we used event-related repetitive dual pulse transcranial magnetic stimulation to interfere with neural activity in the right frontal eye field (rFEF) and posterior parietal cortex (rPPC). This procedure allowed us to explore how inhibiting rFEF and rPPC influences shifts of attention triggered by the observation of body-related (gaze and hand) and non body-related (arrow) directional distractors. Participants were asked to perform a leftward or rightward pointing movement according to the color change of a central imperative signal while ignoring a distractor, which was either a gaze, a pointing hand or an arrow. Stimulation of rPPC in a region supposedly linked to attentional re-orienting and to planning and execution of upper limb movements increased the reflexive tendency to follow distracting pointing hands but not oriented gaze or arrows. These findings suggest that inhibition of cortical structures that control attentional shifts triggered by social stimuli brings forth an increase of the cost of attentional re-orienting. Moreover, our results provide the first causative evidence that reflexive social attention in humans may be coded according to body-part-centered frames of reference.
在人类和非人类灵长类动物等高度社会化的群体中，目光注视和指向线索对于引导同种个体的注意力至关重要。尽管神经影像学研究表明，观察社会线索引发的注意力转移会激活旁观者的额顶叶皮层，但关于这些区域在社会注意力的定向和重新定向中是否起因果作用的信息尚缺。为了增进我们对此的理解，我们使用事件相关重复双脉冲经颅磁刺激来干扰右侧额叶眼区（rFEF）和顶叶后皮质（rPPC）的神经活动。这一过程使我们能够探究抑制rFEF和rPPC如何影响由观察与身体相关（目光注视和手部动作）和非身体相关（箭头）的定向干扰物所引发的注意力转移。参与者被要求根据中央指令信号的颜色变化向左或向右做指向动作，同时忽略一个干扰物，该干扰物可以是一道目光、一只指向的手或一个箭头。在一个据推测与注意力重新定向以及上肢运动的计划和执行相关的区域对rPPC进行刺激，增加了跟随干扰性指向手的反射倾向，但对定向的目光或箭头则没有影响。这些发现表明，抑制控制由社会刺激引发的注意力转移的皮质结构会导致注意力重新定向成本的增加。此外，我们的结果首次提供了因果证据，表明人类的反射性社会注意力可能是根据以身体部位为中心的参照系进行编码的。
