ABSTRACT

We have identified the brain areas involved in Manual Preference (MP) in 143 left-handers (LH) and 144 right-handers (RH). First, we selected the pairs of homotopic regions of interest (hROIs) of the AICHA atlas with significant contralateral activation and asymmetry during the right hand and the left hand Finger-Tapping (FT) both in RH and LH. Thirteen hROIs were selected, including the primary and secondary sensorimotor and premotor cortices, thalamus, dorsal putamen, and cerebellar lobule IV. In both groups, contralateral activations and ipsilateral deactivations were seen, with stronger asymmetries when the preferred hand was used. Comparing with different models for the prediction of MP, we found that the differences in activity during preferred hand minus non-preferred hand movement in 11 contralateral and/or ipsilateral hROIS were best at explaining handedness distribution. Two different mechanisms were identified: 1. Stronger contralateral activity of cortical and cerebellar motor areas during right hand movement, seen in both groups but modulated by handedness; 2. Stronger deactivation in ipsilateral areas during dominant hand movement in both groups, LH here mirroring RH. The present study thus demonstrates that handedness neural support is complex and not simply based on a mirrored organization of hand motor areas.

摘要

我们已经确定了 143 名左撇子 (LH) 和 144 名右撇子 (RH) 的手动偏好 (MP) 所涉及的大脑区域。首先，我们选择了在右手和左手手指敲击 (FT) 期间在 RH 和 LH 中具有显着对侧激活和不对称性的 AICHA 图谱的同伦感兴趣区域 (hROI) 对。选择了 13 个 hROI，包括初级和次级感觉运动和前运动皮质、丘脑、背壳核和小脑小叶 IV。在两组中，都看到了对侧激活和同侧失活，当使用首选手时，不对称性更强。与不同的 MP 预测模型相比，我们发现，在 11 个对侧和/或同侧 hROIS 中，首选手减去非首选手运动期间的活动差异最能解释惯用手的分布。确定了两种不同的机制： 1. 右手运动期间皮层和小脑运动区的对侧活动更强，在两组中都可见，但受惯用习惯的影响；2. 两组的优势手运动期间同侧区域的失活更强，此处的 LH 反映了 RH。因此，本研究表明，惯用手的神经支持是复杂的，而不仅仅是基于手部运动区域的镜像组织。两组均可见，但受惯用手的影响；2. 两组的优势手运动期间同侧区域的失活更强，此处的 LH 反映了 RH。因此，本研究表明，惯用手的神经支持是复杂的，而不仅仅是基于手部运动区域的镜像组织。两组均可见，但受惯用手的影响；2. 两组的优势手运动期间同侧区域的失活更强，此处的 LH 反映了 RH。因此，本研究表明，惯用手的神经支持是复杂的，而不仅仅是基于手部运动区域的镜像组织。