Straka Hans, Lambert François M, Pfanzelt Sandra, Beraneck Mathieu
Laboratoire de Neurobiologie des Réseaux Sensorimoteurs, CNRS UMR 7060-Université Paris Descartes, Paris, France.
Ann N Y Acad Sci. 2009 May;1164:37-44. doi: 10.1111/j.1749-6632.2008.03740.x.
Self-generated locomotor activity is accompanied by head movements that cause retinal image displacements with a resultant degradation of visual information processing. To maintain visual acuity, retinal image drift must be counteracted by dynamic compensatory gaze adjustments that derive to a large extent from vestibulo-ocular reflexes (VOR). During head motion, vestibular signals code a wide frequency range from static head position to high acceleration profiles during rapid head turns. This large dynamic range suggests that the sensory-motor transformation occurs in parallel, yet complementary frequency-tuned pathways. In fact, the classic "three-neuronal" VOR pathway is composed of distinct functional subgroups of cells with different intrinsic properties and response dynamics at each synaptic level. This generates sets of neuronal filters that are ideal for particular frequency ranges and signaling patterns, respectively. In second-order vestibular subgroups, different filter functions, and hence a different synaptic processing is facilitated by a coadaptation of intrinsic membrane and emerging network properties. The consecutive assembly and sequential connectivity of pre- and postsynaptic neuronal elements with corresponding physiological properties, generates parallel pathways that allow for separate coding of different dynamic head-motion components during locomotor activity.
自我产生的运动活动伴随着头部运动，这会导致视网膜图像位移，进而使视觉信息处理能力下降。为了保持视力，视网膜图像漂移必须通过动态补偿性眼动调整来抵消，这种调整在很大程度上源于前庭眼反射（VOR）。在头部运动期间，前庭信号编码从静态头部位置到快速转头时的高加速度曲线等广泛的频率范围。这个大的动态范围表明感觉运动转换是在并行但互补的频率调谐通路中发生的。事实上，经典的“三神经元”VOR通路由不同功能的细胞亚群组成，在每个突触水平具有不同的内在特性和反应动力学。这产生了分别适用于特定频率范围和信号模式的神经元滤波器组。在二阶前庭亚群中，内在膜和新兴网络特性的共同适应促进了不同的滤波器功能，从而实现了不同的突触处理。具有相应生理特性的突触前和突触后神经元元件的连续组装和顺序连接，产生了并行通路，允许在运动活动期间对不同的动态头部运动成分进行单独编码。
