Pre-receptor profile of sensory images and primary afferent neuronal representation in the mormyrid electrosensory system
Pre-receptor profile of sensory images and primary afferent neuronal representation in the mormyrid electrosensory system
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DOI：
10.1242/jeb.01053
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发表时间：
2004-06-01
影响因子：
2.8
通讯作者：
Caputi, AA
中科院分区：
文献类型：
--
作者：
Gómez, L;Budelli, R;Caputi, AA
本文探讨了拟颌鱼Gnathonemuspetersii的电感觉叶对鱼自身电器官放电的传入反应。为了理解自然感觉图像的神经编码，当不同导电性的物体被放置在沿着鱼的皮肤的不同位置沿着时，即在外周感受野内和外周感受野外的不同点处，检查反应。在鱼的自生电场中的物体的存在产生经皮电流密度的局部调制。局部电器官放电的测量表明，在电感受感觉表面形成的对象图像具有相反的中心环绕，“墨西哥帽”的配置文件。这是一种感受器前现象，是感觉刺激的物理性质所固有的，发生在神经侧抑制之前，不依赖于这种中枢抑制。刺激强度被编码在初级传入纤维反应的潜伏期和动作电位的数量中。它也反映在电感觉叶的深颗粒层中记录的胞外场电位的幅度和面积的变化中。由于对象图像由接受表面上的电流密度的重新分布组成，因此其存在通过比面向对象的皮肤表面大得多的区域上的受体活性的变化来编码。我们的结论是，每个受体编码的信息来自整个场景的方式，可能看起来模糊时，从一个单一的点，为了提取特定的对象的功能，大脑必须处理的电图像表示在整个感官表面。
Afferent responses to the fish's own electric organ discharge were explored in the electrosensory lobe of the mormyrid fish Gnathonemus petersii. In order to understand the neural encoding of natural sensory images, responses were examined while objects of different conductivities were placed at different positions along the skin of the fish, i.e. at different points within, and also outside, peripheral receptive fields. The presence of an object in the fish's self-generated electric field produces local modulation of transcutaneous current density. Measurement of the local electric organ discharge shows that object images formed at the electroreceptive sensory surface have an opposing center-surround, 'Mexican hat' profile. This is a pre-receptor phenomenon intrinsic to the physical nature of the sensory stimulus that takes place prior to neural lateral inhibition and is independent of such central inhibition.Stimulus intensity is encoded in the latency and number of action potentials in the response of primary afferent fibers. It is also reflected in changes in the amplitude and area of extracellular field potentials recorded in the deep granular layer of the electrosensory lobe. Since the object image consists of a redistribution of current density over the receptive surface, its presence is coded by change in the activity of receptors over an area much larger than the skin surface facing the object. We conclude that each receptor encodes information coming from the whole scene in a manner that may seem ambiguous when seen from a single point and that, in order to extract specific object features, the brain must process the electric image represented over the whole sensory surface.