Bastian J
Department of Zoology, University of Oklahoma, Norman 73019.
J Comp Physiol A. 1995 Jan;176(1):63-73. doi: 10.1007/BF00197753.
Recordings within the posterior eminentia granularis of the weakly electric fish, Apteronotus leptorhynchus, revealed multiple types of proprioceptive units responsive to changes in the position of the animal's trunk and tail. Intracellular labelling showed that the proprioceptor recordings were made from axons that ramify extensively within the EGp. The location of the somata giving rise to these axons is presently unknown. Electroreceptor afferent responses to electric organ discharge amplitude modulations caused by movement of the animal's tail were compared to responses caused by electronically generated AMs of similar amplitude and time course. These did not differ. Electrosensory lateral line lobe pyramidal cells responded significantly less to electric organ discharge amplitude modulations caused by changing the animal's posture as compared to electronically produced AMs, suggesting that central mechanisms attenuate pyramidal cell responses to reafferent electrosensory inputs. Experiments in which the pattern of reafferent input associated with changes in posture was altered revealed that the pyramidal cells learn, over a time course of several minutes, to reject new patterns of input. Both proprioceptive input and descending electrosensory input to the posterior eminentia granularis are involved in generating the observed plastic changes in pyramidal cell responsiveness.
对弱电鱼线翎电鳗（Apteronotus leptorhynchus）颗粒状后隆起内的记录显示，有多种本体感受单元对动物躯干和尾巴位置的变化做出反应。细胞内标记表明，本体感受器记录是由在颗粒状后隆起（EGp）内广泛分支的轴突产生的。产生这些轴突的胞体位置目前尚不清楚。将电感受器对动物尾巴运动引起的电器官放电幅度调制的传入反应与由电子产生的幅度和时间进程相似的调幅反应进行了比较。两者没有差异。与电子产生的调幅相比，电感觉侧线叶锥体细胞对动物姿势改变引起的电器官放电幅度调制的反应明显较小，这表明中枢机制会减弱锥体细胞对再传入电感觉输入的反应。改变与姿势变化相关的再传入输入模式的实验表明，锥体细胞在几分钟的时间过程中学会拒绝新的输入模式。颗粒状后隆起的本体感受输入和下行电感觉输入都参与了锥体细胞反应性中观察到的可塑性变化的产生。
