Behrend Oliver, Branoner Francisco, Zhivkov Zhivko, Ziehm Ulrike
Aquatic Bioacoustics Laboratory, Institute of Biology, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany.
Eur J Neurosci. 2006 Feb;23(3):729-44. doi: 10.1111/j.1460-9568.2006.04577.x.
Many aquatic vertebrates use mechano-sensory lateral lines to decipher water movements. The peripheral and central organization of the lateral line system has much in common with the auditory system. Therefore, it was hypothesized that the information processing of both systems could be related. Analogous to acoustic objects, for instance, object representations along the central lateral line pathway must be generated from patterns of particle motion across peripheral receivers. Thus, the lateral line offers insight into key features of neural computation beyond a specific sensory system. Here, central processing of water surface waves was described in the African clawed frog which depends on wave signals for prey detection, recognition and localization. Neural responses to surface wave stimuli were recorded in the brainstem and midbrain of Xenopus. A total of 109 units displayed either excitatory or inhibitory responses to surface waves. The response pattern distribution differed significantly across the optic tectum and torus semicircularis magnocellularis (chi-square test, P < 0.05). Stimulus frequencies from 10 to 40 Hz were represented equally across lateral line nuclei but best frequencies were systematically distributed along the rostrocaudal axis of the midbrain (chi-square test, P < 0.05). Forty-one percent of 102 widely distributed units phase locked significantly to stimulus frequencies (Rayleigh test, P < 0.05; vector strength > 0.3) and 41% of 39 tested units featured non-monotone rate-level functions. These neurones were registered mainly in the dorsal tectum and magnocellular torus semicircularis (chi-square test, P < 0.05). Across all tested nuclei, 16 of 17 discreetly distributed units showed a directional response to spatial stimulation. The results suggest midbrain subdivisions with respect to processing of stimulus timing, frequency and amplitude.
许多水生脊椎动物利用机械感觉侧线来解读水流运动。侧线系统的外周和中枢组织与听觉系统有许多共同之处。因此，有人推测这两个系统的信息处理可能有关联。例如，类似于声学物体，沿中枢侧线通路的物体表征必须从外周感受器上的粒子运动模式中生成。因此，侧线为深入了解特定感觉系统之外的神经计算关键特征提供了线索。在此，描述了非洲爪蟾对水面波的中枢处理过程，非洲爪蟾依靠波信号来检测、识别和定位猎物。在非洲爪蟾的脑干和中脑记录了对表面波刺激的神经反应。共有109个单位对表面波表现出兴奋性或抑制性反应。视顶盖和半规管大细胞环的反应模式分布有显著差异（卡方检验，P < 0.05）。10至40赫兹的刺激频率在侧线核中均有体现，但最佳频率沿中脑的前后轴呈系统分布（卡方检验，P < 0.05）。102个广泛分布的单位中有41%对刺激频率有显著的锁相（瑞利检验，P < 0.05；矢量强度> 0.3），39个测试单位中有41%具有非单调的频率-强度函数。这些神经元主要记录在背侧顶盖和半规管大细胞环中（卡方检验，P < 0.05）。在所有测试核中，17个离散分布的单位中有16个对空间刺激表现出定向反应。结果表明中脑在刺激时间、频率和幅度的处理方面存在细分。
