Migliaro Adriana, Caputi Angel A, Budelli Ruben
Sección Biomatemática, Instituto de Biología, Facultad de Ciencias, Montevideo, Uruguay.
PLoS Comput Biol. 2005 Jul;1(2):123-31. doi: 10.1371/journal.pcbi.0010016. Epub 2005 Jul 15.
Electroreceptive fish detect nearby objects by processing the information contained in the pattern of electric currents through the skin. The distribution of local transepidermal voltage or current density on the sensory surface of the fish's skin is the electric image of the surrounding environment. This article reports a model study of the quantitative effect of the conductance of the internal tissues and the skin on electric image generation in Gnathonemus petersii (Günther 1862). Using realistic modelling, we calculated the electric image of a metal object on a simulated fish having different combinations of internal tissues and skin conductances. An object perturbs an electric field as if it were a distribution of electric sources. The equivalent distribution of electric sources is referred to as an object's imprimence. The high conductivity of the fish body lowers the load resistance of a given object's imprimence, increasing the electric image. It also funnels the current generated by the electric organ in such a way that the field and the imprimence of objects in the vicinity of the rostral electric fovea are enhanced. Regarding skin conductance, our results show that the actual value is in the optimal range for transcutaneous voltage modulation by nearby objects. This result suggests that "voltage" is the answer to the long-standing question as to whether current or voltage is the effective stimulus for electroreceptors. Our analysis shows that the fish body should be conceived as an object that interacts with nearby objects, conditioning the electric image. The concept of imprimence can be extended to other sensory systems, facilitating the identification of features common to different perceptual systems.
电感受性鱼类通过处理流经皮肤的电流模式中所包含的信息来探测附近的物体。鱼皮肤感觉表面上局部经表皮电压或电流密度的分布就是周围环境的电图像。本文报道了一项关于彼得氏裸臀鱼（Günther，1862）体内组织和皮肤电导对电图像生成的定量影响的模型研究。通过逼真的建模，我们计算了在具有不同体内组织和皮肤电导组合的模拟鱼身上金属物体的电图像。一个物体对电场的扰动就如同它是一个电源分布一样。电源的等效分布被称为物体的电印。鱼体的高导电性降低了给定物体电印的负载电阻，增强了电图像。它还以这样一种方式引导发电器官产生的电流，使得吻部电凹附近物体的电场和电印得到增强。关于皮肤电导，我们的结果表明，实际值处于附近物体对经皮电压进行调制的最佳范围内。这一结果表明，“电压”是关于电流还是电压是电感受器的有效刺激这一长期问题的答案。我们的分析表明，鱼体应被视为一个与附近物体相互作用、调节电图像的物体。电印的概念可以扩展到其他感觉系统，有助于识别不同感知系统共有的特征。
