Immisch I, Waldvogel D, van Gelderen P, Hallett M
Human Motor Control Section, NINDS, NIH, Bethesda, MD 20892, USA.
Neuroimage. 2001 Sep;14(3):674-84. doi: 10.1006/nimg.2001.0856.
The medial wall of the frontal cortex is thought to play an important role for bimanual coordination. However, there is uncertainty regarding the exact neuroanatomical regions involved. We compared the activation patterns related to bimanual movements using functional magnetic resonance imaging in 12 healthy right-handed subjects, paying special attention to the anatomical variability of the frontal medial wall. The subjects performed unimanual right and left and bimanual antiphase and in-phase flexion and extension movements of the index finger. Activation of the right supplementary motor area (SMA) proper, right and left caudal cingulate motor area (CMA), and right and left premotor cortices was significantly stronger during bimanual antiphase than bimanual in-phase movements, indicating an important function of these areas with bimanual coordination. A frequent anatomical variation is the presence of the paracingulate sulcus (PCS), which might be an anatomical landmark to determine the location of activated areas. Seven subjects had a bilateral, three a unilateral right, and two a unilateral left PCS. Because the area around the PCS is functionally closer coupled to the CMA than to the SMA, activation found in the area around the PCS should be attributed to the CMA. With anatomical variations such as the presence of a PCS or a vertical branch of the cingulate sulcus, normalization and determination of the activation with the help of stereotaxic coordinates can cause an incorrect shift of CMA activation to the SMA. This might explain some of the discrepancies found in previous studies.
额叶皮质的内侧壁被认为在双手协调中起着重要作用。然而，对于具体涉及的神经解剖区域仍存在不确定性。我们使用功能磁共振成像比较了12名健康右利手受试者与双手运动相关的激活模式，特别关注额叶内侧壁的解剖变异性。受试者进行了右手和左手的单手指运动以及双手的反相和同相屈伸运动。在双手反相运动期间，右侧辅助运动区（SMA）固有部分、左右尾侧扣带回运动区（CMA）以及左右运动前皮质的激活明显强于双手同相运动，表明这些区域在双手协调中具有重要功能。一种常见的解剖变异是旁扣带回沟（PCS）的存在，它可能是确定激活区域位置的解剖标志。7名受试者双侧存在PCS，3名受试者单侧右侧存在PCS，2名受试者单侧左侧存在PCS。由于PCS周围区域在功能上与CMA的耦合比与SMA更紧密，在PCS周围区域发现的激活应归因于CMA。存在PCS或扣带回沟垂直分支等解剖变异时，借助立体定向坐标进行标准化和激活测定可能会导致CMA激活向SMA的错误偏移。这可能解释了先前研究中发现的一些差异。
