Beloozerova I, Rossignol S
Centre de Recherche en Sciences Neurologiques, Faculté de Médecine, Pavillon Paul-G.-Desmarais, 2960 Chemin de la Tour, Université de Montréal, Montréal, Québec, Canada.
Brain Res. 1999 Oct 30;846(1):87-105. doi: 10.1016/s0006-8993(99)01967-8.
Spontaneous rhythmic antidromic discharges have previously been recorded in proximal stumps of cut dorsal roots during locomotion (real and fictive). The goals of the present study were to elucidate (1) whether both orthodromic and antidromic discharges occur in the same dorsal root filament and (2) whether orthodromic discharges have an influence upon antidromic discharges of units in the same filament. Unitary activity was recorded in 70 uncut dorsal root filaments (L6-S1) in 15 decerebrate cats using bipolar Ag/AgCl electrodes. Spikes with similar wave shapes were considered to represent the activity of single units. Spike-triggered averaging (STA), local anaesthesia and transection of filaments were used to determine the direction of propagation of spikes. Spikes with different initial electrical polarities were found in most of the filaments and shown to propagate in opposite directions at rest and during fictive locomotion. On average, there were 38%+/-S.D. 23% antidromically discharging units per filament and their mean conduction velocity was 55 m/s+/-S.D. 25 m/s. After blocking orthodromic activity of the whole filament by a transection or local anesthesia applied distally to the recording site, changes were seen in the antidromic discharges of some units suggesting that spontaneous orthodromic discharges normally seen in the filament may influence the antidromic discharges of some units. Moreover, out of 27 antidromic units recorded during fictive locomotion, 12 were rhythmically modulated with peak discharges occurring in various parts of the locomotor cycle. We conclude that, in uncut dorsal roots, there is a normal coexistence of spontaneous orthodromic and antidromic discharges revealed by STA and that there is an interaction between spontaneous orthodromic and antidromic discharges.
先前在运动（真实运动和虚拟运动）过程中，已在切断的背根近端残端记录到自发性节律性逆向放电。本研究的目的是阐明：（1）正向和逆向放电是否发生在同一背根细丝中；（2）正向放电是否会对同一细丝中神经元的逆向放电产生影响。在15只去大脑猫的70根未切断的背根细丝（L6-S1）中，使用双极银/氯化银电极记录单一神经元活动。波形相似的尖峰被认为代表单个神经元的活动。采用尖峰触发平均法（STA）、局部麻醉和细丝横断来确定尖峰的传播方向。在大多数细丝中发现了具有不同初始电极性的尖峰，并显示在静息和虚拟运动期间沿相反方向传播。平均而言，每根细丝中有38%±标准差23%的逆向放电神经元，其平均传导速度为55米/秒±标准差25米/秒。在通过横断或在记录部位远端施加局部麻醉阻断整个细丝的正向活动后，一些神经元的逆向放电出现了变化，这表明细丝中通常所见的自发性正向放电可能会影响一些神经元的逆向放电。此外，在虚拟运动期间记录的27个逆向放电神经元中，有12个受到节律性调制，在运动周期的不同阶段出现放电峰值。我们得出结论，在未切断的背根中，STA显示出自发性正向和逆向放电正常共存，并且自发性正向和逆向放电之间存在相互作用。
