Analysis of the internal local activity distribution in human skeletal muscles is important for managing muscle fatigue/pain and dysfunction. However, no method is established for three-dimensional (3D) statistical analysis of features of activity regions common to multiple subjects during voluntary motor tasks. We investigated the characteristics of muscle activity distribution from the data of ten healthy subjects (29 ± 1 year old, 2 women) during voluntary teeth clenching under two different occlusal conditions by applying spatial normalization and statistical parametric mapping (SPM) to analysis of muscle functional magnetic resonance imaging (mfMRI) using increase in transverse relaxation time (T2) of the skeletal muscle induced by exercise. The expansion of areas with significant T2 increase was observed in the masticatory muscles after clenching with molar loss comparing with intact dentition. The muscle activity distribution characteristics common to a group of subjects, i.e., the active region in the temporal muscle ipsilateral to the side with the molar loss and medial pterygoid muscle contralateral to the side with the molar loss, were clarified in 3D by applying spatial normalization and SPM to mfMRI analysis. This method might elucidate the functional distribution within the muscles and the localized muscular activity related to skeletal muscle disorders.

分析人体骨骼肌内部局部活动分布对于管理肌肉疲劳/疼痛和功能障碍很重要。然而，在自愿运动任务期间，没有建立对多个受试者共有的活动区域特征的三维 (3D) 统计分析的方法。我们通过应用空间归一化和统计参数映射 (SPM) 分析肌肉功能，从 10 名健康受试者（29 ± 1 岁，2 名女性）在两种不同咬合条件下自愿咬牙期间的数据研究肌肉活动分布的特征。使用运动引起的骨骼肌横向弛豫时间 (T2) 增加的磁共振成像 (mfMRI)。与完整牙列相比，在磨牙缺失的情况下，在咬合肌中观察到 T2 显着增加的区域扩大。通过应用空间归一化在 3D 中阐明了一组受试者共有的肌肉活动分布特征，即与磨牙缺失一侧同侧的颞肌活动区域和与磨牙缺失一侧对侧的内侧翼状肌和 SPM 到 mfMRI 分析。这种方法可能阐明肌肉内的功能分布和与骨骼肌疾病相关的局部肌肉活动。通过将空间归一化和 SPM 应用于 mfMRI 分析，在 3D 中阐明了与磨牙缺失一侧同侧的颞肌活动区域和与磨牙缺失一侧对侧的内侧翼肌。这种方法可能阐明肌肉内的功能分布和与骨骼肌疾病相关的局部肌肉活动。通过将空间归一化和 SPM 应用于 mfMRI 分析，在 3D 中阐明了与磨牙缺失一侧同侧的颞肌活动区域和与磨牙缺失一侧对侧的内侧翼肌。这种方法可能阐明肌肉内的功能分布和与骨骼肌疾病相关的局部肌肉活动。