Drushel R F, Neustadter D M, Hurwitz I, Crago P E, Chiel H J
Department of Biology, Case Western University, Cleveland, OH 44106-7080, USA.
J Exp Biol. 1998 May;201(Pt 10):1563-83. doi: 10.1242/jeb.201.10.1563.
The feeding behavior of the marine mollusc Aplysia californica is an intensively studied model system for understanding the neural control of behavior. Feeding movements are generated by contractions of the muscles of the buccal mass. These muscles are internal and cannot be visualized during behavior. In order to infer the movements of the muscles of the buccal mass, two kinematic models were constructed. The first kinematic model assumed that the complex consisting of the pincer-like radula and the underlying odontophore was spherical in shape. In this model, the radula/odontophore was moved anteriorly or posteriorly and the more superficial buccal muscles (I1/I3 and I2) were fitted around it. Although the overall buccal mass shapes predicted by this model were similar to those observed in vivo during protraction, the shapes predicted during retraction were very different. We therefore constructed a second kinematic model in which the shape of the radula/odontophore was based on the shapes assumed by those structures in vitro when they were passively forced into protraction, rest or retraction positions. As each of these shapes was rotated, the second kinematic model generated overall shapes of the buccal mass that were similar to those observed in vivo during swallowing and tearing, and made predictions about the antero-posterior length of the buccal mass and the relative location of the lateral groove. These predictions were consistent with observations made in vivo and in vitro. The kinematic patterns of intrinsic buccal muscles I1 and I2 in vivo were estimated using the second model. Both models make testable predictions with regard to the functions and neural control of intrinsic buccal muscles I2 and I3.
海兔（加州海兔）的摄食行为是一个经过深入研究的模型系统，用于理解行为的神经控制。摄食运动由口球肌肉的收缩产生。这些肌肉位于内部，在行为过程中无法可视化。为了推断口球肌肉的运动，构建了两个运动学模型。第一个运动学模型假设由钳状齿舌和下方的齿舌载体组成的复合体呈球形。在这个模型中，齿舌/齿舌载体向前或向后移动，更表层的口球肌肉（I1/I3和I2）围绕着它。尽管该模型预测的口球整体形状与在伸展过程中体内观察到的形状相似，但在收缩过程中预测的形状却大不相同。因此，我们构建了第二个运动学模型，其中齿舌/齿舌载体的形状基于这些结构在体外被动地被强制进入伸展、静止或收缩位置时所假设的形状。随着这些形状中的每一个旋转，第二个运动学模型生成的口球整体形状与在吞咽和撕裂过程中体内观察到的形状相似，并对口球的前后长度和侧沟的相对位置做出了预测。这些预测与体内和体外的观察结果一致。使用第二个模型估计了体内口球固有肌肉I1和I2的运动模式。两个模型都对口球固有肌肉I2和I3的功能和神经控制做出了可检验的预测。
