Caceres Alejandra Harris, Barany Deborah A, Dundon Neil M, Smith Jolinda, Marneweck Michelle
Department of Human Physiology, University of Oregon, Eugene, Oregon 97403.
Department of Kinesiology, University of Georgia, Athens, Georgia 30602.
eNeuro. 2024 Dec 5;11(12). doi: 10.1523/ENEURO.0405-24.2024. Print 2024 Dec.
Goal-directed actions require transforming sensory information into motor plans defined across multiple parameters and reference frames. Substantial evidence supports the encoding of target direction in gaze- and body-centered coordinates within parietal and premotor regions. However, how the brain encodes the equally critical parameter of target distance remains less understood. Here, using Bayesian pattern component modeling of fMRI data during a delayed reach-to-target task, we dissociated the neural encoding of both target direction and the relative distances between target, gaze, and hand at early and late stages of motor planning. This approach revealed independent representations of direction and distance along the human dorsomedial reach pathway. During early planning, most premotor and superior parietal areas encoded a target's distance in single or multiple reference frames and encoded its direction. In contrast, distance encoding was magnified in gaze- and body-centric reference frames during late planning. These results emphasize a flexible and efficient human central nervous system that achieves goals by remapping sensory information related to multiple parameters, such as distance and direction, in the same brain areas.
目标导向行为需要将感官信息转化为在多个参数和参照系中定义的运动计划。大量证据支持在顶叶和运动前区以注视和身体为中心的坐标系中对目标方向进行编码。然而，大脑如何编码同样关键的目标距离参数仍鲜为人知。在此，我们在一项延迟伸手够目标任务中使用功能磁共振成像（fMRI）数据的贝叶斯模式成分建模，在运动计划的早期和晚期阶段分离了目标方向以及目标、注视和手部之间相对距离的神经编码。这种方法揭示了沿着人类背内侧伸手通路方向和距离的独立表征。在早期计划阶段，大多数运动前区和顶上区在单个或多个参照系中编码目标的距离并编码其方向。相比之下，在晚期计划阶段，以注视和身体为中心的参照系中距离编码得到增强。这些结果强调了灵活且高效的人类中枢神经系统，它通过在同一脑区重新映射与距离和方向等多个参数相关的感官信息来实现目标。
