Zipser B, Bennett M V
J Neurophysiol. 1976 Jul;39(4):693-712. doi: 10.1152/jn.1976.39.4.693.
Activity of neurons in the lateral line lobe was studied by intracellular recording of responses to stimulation of the lateral line nerves and of electroreceptors on the skin surface. Two modes of activation occur for cells responding to inputs from medium receptors. There is a direct monosynaptic input mediated by a single fiber. Short latency of response and antidromic spread from cell to afferent fiber indicate that the mediating synapse is electrotonic. The second input is from a number of additional fibers and is relayed, presumably by the granule cells. At shortest latency this input is disynaptic, probably involving at least one electrotonic synapse. A relay is indicated by heterosynaptic facilitation of the PSP and by pronounced depression with repetitive stimulation. The monosynaptic input may be on the axon. Disynaptic inputs are distributed over the dendrites, and impulses can arise in the dendrites. What appear to be spikes restricted to dendritic regions are often recorded as small brief potentials in the cell body. There is a somatotopic projection of the electroreceptors to the lateral line lobe. The monosynaptic input comes from a specific receptor in the periphery. Strong disynaptic inputs come from a group of receptors generally found anterior, but less commonly posterior or lateral, to the receptor giving rise to the monosynaptic input. Additional inputs that are inhibitory come from surrounding receptors. The inhibition only affects responses to the disynaptic input. The different inputs and multiple sites of impulse initiation must modify the cell's response as compared with the input-output relations that would be obtained with inputs acting on a single summation point. Cells responding to activation of large receptors are infrequent. They are characterized by low threshold, little latency change near threshold, and ability to follow high frequencies of stimulation.
通过细胞内记录对侧线神经和皮肤表面电感受器刺激的反应，研究了侧线叶中神经元的活动。对于对中等感受器输入作出反应的细胞，存在两种激活模式。有一种由单根纤维介导的直接单突触输入。反应潜伏期短以及从细胞向传入纤维的逆向传播表明介导突触是电紧张性的。第二种输入来自许多其他纤维，大概是由颗粒细胞中继的。在最短潜伏期时，这种输入是双突触的，可能涉及至少一个电紧张性突触。PSP的异突触易化和重复刺激时的明显抑制表明存在中继。单突触输入可能在轴突上。双突触输入分布在树突上，并且冲动可在树突中产生。在树突区域受限的尖峰通常在细胞体中记录为小的短暂电位。电感受器到侧线叶存在躯体定位投射。单突触输入来自外周的特定感受器。强双突触输入来自一组通常在产生单突触输入的感受器前方发现，但较少在其后方或侧面发现的感受器。额外的抑制性输入来自周围的感受器。这种抑制仅影响对双突触输入的反应。与作用于单个总和点的输入所获得的输入 - 输出关系相比，不同的输入和多个冲动起始位点必定会改变细胞的反应。对大感受器激活作出反应的细胞很少见。它们的特征是阈值低、阈值附近潜伏期变化小以及能够跟随高频刺激。
