Bastian J, Courtright J, Crawford J
Department of Zoology, University of Oklahoma, Norman 73019.
J Comp Physiol A. 1993 Sep;173(3):257-74. doi: 10.1007/BF00212690.
Extracellular injections of horseradish peroxidase were used to label commissural cells connecting the electrosensory lateral line lobes of the weakly electric fish Apteronotus leptorhynchus. Multiple commissural pathways exist; a caudal commissure is made up of ovoid cell axons, and polymorphic cells' axons project via a rostral commissure. Intracellular recording and labeling showed that ovoid cells discharge spontaneously at high rates, fire at preferred phases to the electric organ discharge, and respond to increased receptor afferent input with short latency partially adapting excitation. Ovoid cell axons ramify extensively in the rostro-caudal direction but are otherwise restricted to a single ELL subdivision. Polymorphic cells are also spontaneously active, but their firing is unrelated to the electric organ discharge waveform. They respond to increased receptor afferent activity with reduced firing frequency and response latency is long. Electrical stimulation of the commissural axons alters the behavior of pyramidal cells in the contralateral ELL. Basilar pyramidal cells are hyperpolarized and nonbasilar pyramidal cells are depolarized by this type of stimulation. The physiological results indicate that the ovoid cells participate in common mode rejection mechanisms and also suggest that the ELLs may function in a differential mode in which spatially restricted electrosensory stimuli can evoke heightened responses.
通过向细胞外注射辣根过氧化物酶来标记连接弱电鱼线纹南美长颌鱼电感觉侧线叶的连合细胞。存在多条连合通路；一条尾侧连合由卵圆形细胞的轴突组成，多形细胞的轴突则通过一条吻侧连合投射。细胞内记录和标记显示，卵圆形细胞以高频率自发放电，在电鳔放电的偏好相位放电，并以短潜伏期部分适应性兴奋对增加的感受器传入输入做出反应。卵圆形细胞的轴突在吻尾方向广泛分支，但在其他方面局限于单个电感觉侧线叶分区。多形细胞也具有自发活性，但其放电与电鳔放电波形无关。它们对增加的感受器传入活动以降低的放电频率做出反应，且反应潜伏期较长。对连合轴突进行电刺激会改变对侧电感觉侧线叶中锥体细胞的行为。这种类型的刺激会使基底锥体细胞超极化，使非基底锥体细胞去极化。生理学结果表明，卵圆形细胞参与共模抑制机制，也表明电感觉侧线叶可能以一种差异模式发挥作用，即空间受限的电感觉刺激可引发增强的反应。
