Laurens Jean, Liu Sheng, Yu Xiong-Jie, Chan Raymond, Dickman David, DeAngelis Gregory C, Angelaki Dora E
Department of Neuroscience, Baylor College of Medicine, Houston, United States.
State Key Laboratory of Ophthalmology, Zhongshan Opthalmic Center, Sun Yat-sen University, Guangzhou, China.
Elife. 2017 Jan 11;6:e20787. doi: 10.7554/eLife.20787.
Sensory signals undergo substantial recoding when neural activity is relayed from sensors through pre-thalamic and thalamic nuclei to cortex. To explore how temporal dynamics and directional tuning are sculpted in hierarchical vestibular circuits, we compared responses of macaque otolith afferents with neurons in the vestibular and cerebellar nuclei, as well as five cortical areas, to identical three-dimensional translational motion. We demonstrate a remarkable spatio-temporal transformation: otolith afferents carry spatially aligned cosine-tuned translational acceleration and jerk signals. In contrast, brainstem and cerebellar neurons exhibit non-linear, mixed selectivity for translational velocity, acceleration, jerk and position. Furthermore, these components often show dissimilar spatial tuning. Moderate further transformation of translation signals occurs in the cortex, such that similar spatio-temporal properties are found in multiple cortical areas. These results suggest that the first synapse represents a key processing element in vestibular pathways, robustly shaping how self-motion is represented in central vestibular circuits and cortical areas.
当神经活动从前庭感受器经丘脑前核团和丘脑核团传导至皮层时，感觉信号会经历大量的重新编码。为了探究在层级式前庭回路中时间动态和方向调谐是如何形成的，我们比较了猕猴耳石传入神经与前庭核、小脑核以及五个皮层区域的神经元对相同三维平移运动的反应。我们证明了一种显著的时空转换：耳石传入神经携带空间对齐的余弦调谐平移加速度和急动信号。相比之下，脑干和小脑神经元对平移速度、加速度、急动和位置表现出非线性的混合选择性。此外，这些成分通常表现出不同的空间调谐。平移信号在皮层中进一步发生适度转换，使得在多个皮层区域发现了相似的时空特性。这些结果表明，第一个突触代表前庭通路中的关键处理元件，有力地塑造了自我运动在中枢前庭回路和皮层区域中的表征方式。
