Department of Epileptology, University of Bonn Medical Center, Bonn, Germany.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2012 Jan;198(1):1-10. doi: 10.1007/s00359-011-0681-2. Epub 2011 Sep 30.
Paddlefish are uniquely adapted for the detection of their prey, small water fleas, by primarily using their passive electrosensory system. In a recent anatomical study, we found two populations of secondary neurons in the electrosensory hind brain area (dorsal octavolateral nucleus, DON). Cells in the anterior DON project to the contralateral tectum, whereas cells in the posterior DON project bilaterally to the torus semicircularis and lateral mesencephalic nucleus. In this study, we investigated the properties of both populations and found that they form two physiologically different populations. Cells in the posterior DON are about one order of magnitude more sensitive and respond better to stimuli with lower frequency content than anterior cells. The posterior cells are, therefore, better suited to detect distant prey represented by low-amplitude signals at the receptors, along with a lower frequency spectrum, whereas cells in the anterior DON may only be able to sense nearby prey. This suggests the existence of two distinct channels for electrosensory information processing: one for proximal signals via the anterior DON and one for distant stimuli via the posterior DON with the sensory input fed into the appropriate ascending channels based on the relative sensitivity of both cell populations.
匙吻鲟主要通过被动电感觉系统来探测其猎物——小型桡足类动物，这使它们具有独特的适应性。在最近的一项解剖学研究中，我们在电感觉后脑区（背侧八叠体外侧核，DON）中发现了两类次级神经元。前 DON 中的细胞投射到对侧的视顶盖，而后 DON 中的细胞则双侧投射到半环体和外侧中脑核。在这项研究中，我们研究了这两类神经元的特性，发现它们形成了两个具有不同生理特性的群体。后 DON 中的细胞比前 DON 中的细胞敏感一个数量级，对低频内容的刺激反应更好。因此，后 DON 中的细胞更适合探测由受体处低幅度信号以及较低频谱表示的远距离猎物，而前 DON 中的细胞可能只能探测到附近的猎物。这表明存在两种不同的电感觉信息处理通道：一种是通过前 DON 进行近距离信号处理，另一种是通过后 DON 进行远距离刺激处理，感觉输入根据这两个细胞群体的相对敏感性，进入适当的上升通道。
