Temporal filtering properties of ampullary electrosensory neurons in the torus semicircularis of Eigenmannia: evolutionary and computational implications.
Temporal filtering properties of ampullary electrosensory neurons in the torus semicircularis of Eigenmannia: evolutionary and computational implications.
复制标题
艾根曼尼亚环半圆壶腹电感觉神经元的时间过滤特性：进化和计算意义。
DOI：
10.1159/000113000
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Rose,GJ
中科院分区：
文献类型：
--
作者：
Fortune,ES;Rose,GJ
弱电鱼有平行的电感觉系统，系统发育上较古老的壶腹系统和新的结节系统。结节系统是一种与主动电定位进化有关的适应。为了探讨壶腹和结节系统的进化关系，我们研究了腹侧半环背侧壶腹神经元的时间过滤特性。使用贴片式移液器在体内进行“全细胞”记录。记录了19个神经元对<40 Hz正弦电信号的反应，并通过注射生物细胞素对这些神经元进行解剖。所有8个低通壶腹神经元都有宽而相对平滑的突触后电位（psps），在低频时很好地反映了正弦刺激。这些神经元具有直径10-14µm的体细胞和粗大的多刺树突。记录8个高通神经元，代表3个生理类别。第一类（3个神经元）的脉冲大致跟随刺激的正弦时间过程；PSP形态与低通神经元相似。第二班有许多小的、快的、个别的哨声；它们的发生率随刺激的不同而变化。最后，四个神经元显示出在刺激频率上宽度恒定的脉冲。三种类型的高通神经元均具有小体（直径8-10µm）、细树突和少棘或无棘。其中一些神经元在树突上有很大的变异。三个神经元具有带通滤波特性：表现出强带通特性的神经元在形态上与低通神经元相似。颞滤过、突触后电位的形状以及环体壶腹和结节神经元的解剖结构的比较表明，环体中结节处理的电路可能是壶腹系统的细化或复制。因此，结节神经元低通滤波特性的机制似乎早于结节系统的进化，并作为干扰避免反应进化的预适应。此外，这些数据支持脊柱密度影响神经元时间过滤特性的假设。
Weakly electric fish have parallel electrosensory systems, the phylogenetically older ampullary system and the novel tuberous system. The tuberous system is an adaptation related to the evolution of active electrolocation. To examine the evolutionary relationship of the ampullary and tuberous systems, the temporal filtering properties of ampullary neurons in the dorsal torus semicircularis ofEigenmanniawere studied. 'Whole-cell' recordings were made in vivo using patch type pipettes. The responses of 19 neurons to sinusoidal electric signals (<40 Hz) were recorded and the anatomy of these neurons demonstrated by injection of biocytin. All eight low-pass ampullary neurons had broad, relatively smooth post-synaptic potentials (psps) that at low frequencies nicely reflected the sinusoidal stimuli. These neurons had somata of 10–14 µm diameter and thick, spiny dendrites. Eight high-pass neurons were recorded, representing three physiological classes. The first class (3 neurons) had psps that roughly followed the sinusoidal time course of the stimulus; the psp morphology was similar to low-pass neurons. The second class had many small, fast, individual psps; their rate of occurrence varied with the stimulus. Finally, four neurons showed psps that were of constant width across stimulus frequencies. All three classes of high-pass neurons had small somata (8–10 µm diameter) with thin dendrites and either few or no spines. Some of these neurons had large varicosities on the dendrites. Three neurons had band-pass filtering properties: neurons that showed strong band-pass properties were morphologically similar to low-pass neurons. Comparisons of the temporal filtering, shapes of post-synaptic potentials, and anatomy of ampullary and tuberous neurons in the torus suggest that the circuitry for tuberous processing in the torus may have evolved as an elaboration or duplication of the ampullary system. The mechanisms underlying the low-pass filtering characteristics of tuberous neurons therefore appear to have predated the evolution of the tuberous system and to have served as a pre-adaptation for the evolution of the jamming avoidance response. In addition, these data support the hypothesis that spine density influences the temporal filtering properties of neurons.