Temporalis function in anthropoids and strepsirrhines: An EMG study
Temporalis function in anthropoids and strepsirrhines: An EMG study
复制标题
DOI：
10.1002/ajpa.20058
复制
发表时间：
2005-09-01
影响因子：
2.8
通讯作者：
Johnson, KR
中科院分区：
文献类型：
--
作者：
Hylander, WL;Wall, CE;Johnson, KR
本研究的主要目的是分析不同类人型和链状灵长类灵长类动物的前后部颞肌肌力募集和放电模式。这个项目有两个具体目标。首先，我们测试了这样的假设，即除了横向肌肉力量外，灵长类动物的联合融合的进化也可能与咀嚼过程中垂直方向的平衡侧肌肉力量有关(Hylander等人。[2000]上午J.Phys.人类刑警组织。112：469-492)。其次，我们测试了这样的假设，即链状动物是否保留了假想的原始哺乳动物的条件来激发前颞肌，而类人猿则具有派生的条件(Wejs[1994]脊椎动物摄食的生物力学；柏林：Springer-Verlag，第282-320页)。记录并分析了狒狒、猕猴、猫头猴、厚尾短尾猴和环尾狐猴左右两侧颞肌前后部的肌电活动。此外，由于我们以工作侧浅咬肌作为参照肌，我们还记录和分析了这些灵长类动物左、右浅咬肌的肌电活动。关于前颞肌的数据没有支持这样的假设，即灵长类动物的联合融合与咀嚼过程中垂直方向的颌肌力有关。因此，灵长类动物的联合融合很可能主要与平衡侧深咬肌的横向定向力量的时机和招募有关(Hylander等人)。[2000]上午J.Phys.人类刑警组织。112：469-492)。此外，我们的数据表明，在链鼻鱼和类人猿中，工作侧和平衡侧前颞肌的放电模式几乎相同。他们的工作和平衡侧的前颞肌不同步地发射，并在力量中风时达到活动的峰值。同样，他们的工作侧和平衡侧的颞后肌也会不同步地发射，并在力量中风时达到活动的峰值。然而，与这些链鼻鱼相比，类人猿的平衡侧后颞肌似乎有一个相对延迟的放电模式。此外，基于其较小的W/B比，类人猿显示出平衡侧后颞肌的肌力募集相对增加。这反过来表明，类人猿在咀嚼过程中可能会强调力量中风的持续时间和幅度。然而，这一假设需要额外的检验。此外，在力量卒中的后期，类人的平衡侧后颞肌的晚期活动明显帮助平衡侧深咬肌驱动工作侧磨牙穿过咬合末端。
The major purpose of this study is to analyze anterior and posterior temporalis muscle force recruitment and firing patterns in various anthropoid and strepsirrhine primates. There are two specific goals for this project. First, we test the hypothesis that in addition to transversely directed muscle force, the evolution of symphyseal fusion in primates may also be linked to vertically directed balancing-side muscle force during chewing (Hylander et al. [2000] Am. J. Phys. Anthropol. 112:469-492). Second, we test the hypothesis of whether strepsirrhines retain the hypothesized primitive mammalian condition for the firing of the anterior temporalis, whereas anthropoids have the derived condition (Weijs [1994] Biomechanics of Feeding in Vertebrates; Berlin: Springer-Verlag, p. 282-320). Electromyographic (EMG) activities of the left and right anterior and posterior temporalis muscles were recorded and analyzed in baboons, macaques, owl monkeys, thick-tailed galagos, and ring-tailed lemurs. In addition, as we used the working-side superficial masseter as a reference muscle, we also recorded and analyzed EMG activity of the left and right superficial masseter in these primates. The data for the anterior temporalis provided no support for the hypothesis that symphyseal fusion in primates is linked to vertically directed jaw muscle forces during mastication. Thus, symphyseal fusion in primates is most likely mainly linked to the timing and recruitment of transversely directed forces from the balancing-side deep masseter (Hylander et al. [2000] Am. J. Phys. Anthropol. 112:469-492). In addition, our data demonstrate that the firing patterns for the working- and balancing-side anterior temporalis muscles are near identical in both strepsirrhines and anthropoids. Their working- and balancing-side anterior temporalis muscles fire asynchronously and reach peak activity during the power stroke. Similarly, their working- and balancing-side posterior temporalis muscles also fire asynchronously and reach peak activity during the power stroke. Compared to these strepsirrhines, however, the balancing-side posterior temporalis of anthropoids appears to have a relatively delayed firing pattern. Moreover, based on their smaller W/B ratios, anthropoids demonstrate a relative increase in muscle-force recruitment of the balancing-side posterior temporalis. This in turn suggests that anthropoids may emphasize the duration and magnitude of the power stroke during mastication. This hypothesis, however, requires additional testing. Furthermore, during the latter portion of the power stroke, the late activity of the balancing-side posterior temporalis of anthropoids apparently assists the balancing-side deep masseter in driving the working-side molars through the terminal portion of occlusion.