Dugué Guillaume P, Tihy Matthieu, Gourévitch Boris, Léna Clément
Neurophysiology of Brain Circuits Team, Institut de Biologie de l'École Normale Supérieure, Inserm U1024, CNRS UMR8197, École Normale Supérieure, PSL Research University, Paris, France.
Genetics and Physiology of Hearing Laboratory, Inserm UMR1120, University Paris 6, Institut Pasteur, Paris, France.
Elife. 2017 Jun 13;6:e26179. doi: 10.7554/eLife.26179.
Head movements are primarily sensed in a reference frame tied to the head, yet they are used to calculate self-orientation relative to the world. This requires to re-encode head kinematic signals into a reference frame anchored to earth-centered landmarks such as gravity, through computations whose neuronal substrate remains to be determined. Here, we studied the encoding of self-generated head movements in the rat caudal cerebellar vermis, an area essential for graviceptive functions. We found that, contrarily to peripheral vestibular inputs, most Purkinje cells exhibited a mixed sensitivity to head rotational and gravitational information and were differentially modulated by active and passive movements. In a subpopulation of cells, this mixed sensitivity underlay a tuning to rotations about an axis defined relative to gravity. Therefore, we show that the caudal vermis hosts a re-encoded, gravitationally polarized representation of self-generated head kinematics in freely moving rats.
头部运动主要是在与头部相关联的参考系中被感知的，然而这些运动却被用于计算相对于世界的自我方位。这就需要通过其神经元基质仍有待确定的计算，将头部运动学信号重新编码到一个以地心为参照的地标（如重力）为锚定的参考系中。在这里，我们研究了大鼠尾侧小脑蚓部对自我产生的头部运动的编码，该区域对重力感知功能至关重要。我们发现，与外周前庭输入相反，大多数浦肯野细胞对头部旋转和重力信息表现出混合敏感性，并且受到主动和被动运动的不同调制。在一个细胞亚群中，这种混合敏感性构成了对围绕相对于重力定义的轴的旋转的调谐基础。因此，我们表明，在自由移动的大鼠中，尾侧蚓部存在自我产生的头部运动学经重新编码的、重力极化的表征。
