Complex pattern of facial remapping in somatosensory cortex following congenital but not acquired hand loss.
Complex pattern of facial remapping in somatosensory cortex following congenital but not acquired hand loss.
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DOI：
10.7554/elife.76158
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发表时间：
2022-12-30
期刊：
影响因子：
7.7
通讯作者：
Makin TR
中科院分区：
文献类型：
--
作者：
Root V;Muret D;Arribas M;Amoruso E;Thornton J;Tarall-Jozwiak A;Tracey I;Makin TR
在初级躯体感觉皮层（S1）中，手部丧失后的皮层重新映射被认为主要由皮层邻近决定，相邻的身体部位重新映射到剥夺区域。传统上，这种重新映射的特点是唇表示的变化，这是假设是直接邻居的手的基础上，在非人类灵长类动物的电生理研究。然而，人类的面部体型的方向是有争议的，对比工作报告了倒置和直立的地形。我们的目的是填补这一空白的S1侏儒调查的地形组织的脸。使用单变量和多变量的方法，我们研究了先天性和后天性缺失的手（以下分别为单手和截肢者），相对于双手控制的个人的脸到手的重新映射的程度。参与者被要求在功能性MRI（fMRI）扫描期间移动不同的面部部位（前额，鼻子，嘴唇，舌头）。我们首先确认了所有三个组中的直立面部组织，上面部而不是嘴唇与手部区域接壤。我们进一步发现几乎没有证据表明截肢者的前额和嘴唇都有重新映射，与他们的幻肢痛（PLP）的慢性程度没有显著关系。相比之下，我们发现了一个复杂的模式，面部重新映射在先天性单手在多个面部部位，其中相对于控制，皮质邻居的位置-前额-显示转移远离剥夺手区，这是随后更多地激活嘴唇和舌头。总之，我们的研究结果表明，人类的面部表征是高度可塑性的，但这种可塑性受到输入剥夺的发展阶段的限制，而不是皮层的接近。
Cortical remapping after hand loss in the primary somatosensory cortex (S1) is thought to be predominantly dictated by cortical proximity, with adjacent body parts remapping into the deprived area. Traditionally, this remapping has been characterised by changes in the lip representation, which is assumed to be the immediate neighbour of the hand based on electrophysiological research in non-human primates. However, the orientation of facial somatotopy in humans is debated, with contrasting work reporting both an inverted and upright topography. We aimed to fill this gap in the S1 homunculus by investigating the topographic organisation of the face. Using both univariate and multivariate approaches we examined the extent of face-to-hand remapping in individuals with a congenital and acquired missing hand (hereafter one-handers and amputees, respectively), relative to two-handed controls. Participants were asked to move different facial parts (forehead, nose, lips, tongue) during functional MRI (fMRI) scanning. We first confirmed an upright face organisation in all three groups, with the upper-face and not the lips bordering the hand area. We further found little evidence for remapping of both forehead and lips in amputees, with no significant relationship to the chronicity of their phantom limb pain (PLP). In contrast, we found converging evidence for a complex pattern of face remapping in congenital one-handers across multiple facial parts, where relative to controls, the location of the cortical neighbour – the forehead – is shown to shift away from the deprived hand area, which is subsequently more activated by the lips and the tongue. Together, our findings demonstrate that the face representation in humans is highly plastic, but that this plasticity is restricted by the developmental stage of input deprivation, rather than cortical proximity.