fMRI Adaptation Reveals a Cortical Mechanism for the Coding of Space Near the Hand
fMRI Adaptation Reveals a Cortical Mechanism for the Coding of Space Near the Hand
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DOI：
10.1523/jneurosci.1172-11.2011
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发表时间：
2011-06-15
影响因子：
5.3
通讯作者：
Ehrsson, H. Henrik
中科院分区：
文献类型：
--
作者：
Brozzoli, Claudio;Gentile, Giovanni;Ehrsson, H. Henrik
人类的行为研究和非人类灵长类动物的电生理记录表明，身体周围的空间存在特定的表征。在猕猴中，在运动前和顶叶区域发现了视觉感受野局限于身体某个部位附近的空间区域的神经元。这些单元格被假设为编码外部对象在以个体身体部位为中心的坐标系中的位置。在本研究中，我们在健康受试者身上使用了fMRI适应范式，揭示了顶内沟前部、顶下叶(缘上回)以及运动前皮质的背侧和腹侧部分对右手附近移动的物体表现出选择性大胆适应的区域。重要的是，如果刺激呈现在较远的空间(100厘米)，或者当手从物体上缩回时，这些区域并不表现出适应。当使用传统的fMRI分析方法时，这种以手为中心的选择性无法被检测到。这些发现很重要，因为它们为人类大脑中近个人空间的表现提供了迄今为止最确凿的神经成像证据。他们还展示了一种由人类手部神经元在运动前和顶后区域实施的选择性机制，并补充了人类和非人类灵长类动物的早期发现。
Behavioral studies in humans and electrophysiological recordings in nonhuman primates have suggested the existence of a specific representation of the space immediately surrounding the body. In macaques, neurons that have visual receptive fields limited to a region of space close around a body part have been found in premotor and parietal areas. These cells are hypothesized to encode the location of external objects in coordinate systems that are centered on individual body parts. In the present study, we used an fMRI adaptation paradigm on healthy participants to reveal areas in the anterior part of the intraparietal sulcus, the inferior parietal lobe (supramarginal gyrus), and the dorsal and ventral portions of the premotor cortex that exhibit selective BOLD adaptation to an object moving near the right hand. Crucially, these areas did not manifest adaptation if the stimulus was presented in far space (100 cm) or when the hand was retracted from the object. This hand-centered selectivity could not be detected when a traditional fMRI analysis approach was used. These findings are important as they provide the most conclusive neuroimaging evidence to date for a representation of near-personal space in the human brain. They also demonstrate a selective mechanism implemented by human perihand neurons in the premotor and posterior parietal areas and add to earlier findings from humans and nonhuman primates.