Bielajew C, Shizgal P
Brain Res. 1982 Apr 8;237(1):107-19. doi: 10.1016/0006-8993(82)90560-1.
The results of collision and refractory period tests were used to compute conduction velocity estimates for reward-relevant neurons activated by electrodes aimed approximately 3 mm apart along the trajectory of the medial forebrain bundle (MFB). Collision tests consisted of delivering pairs of pulses in alternating fashion to the lateral hypothalamus and ventral tegmental area. As the interval between pulses was increased the behavioral effectiveness of double-pulse stimulation abruptly increased and then levelled off at longer pulse-pair intervals. In 6 subjects the C-T interval at which the abrupt rise was observed ranged from 1.0 to 3.0 ms. Refractory periods were estimated using an analogous paradigm but with both pulses applied through the same electrode. Recovery was first evident at pulse-pair intervals greater than 0.4-0.6 ms. Conduction velocity was determined for each subject by dividing the interelectrode distance by the difference between the collision interval and the refractory period; a range of 1.0-4.5 m/s was obtained, values that are inconsistent with the reported conduction velocities for catecholaminergic fibers. It is proposed that the substrate for brain-stimulation reward in the MFB consists of small, myelinated, non-catecholaminergic fibers.
碰撞和不应期测试的结果用于计算由沿着内侧前脑束（MFB）轨迹相距约3毫米的电极激活的与奖励相关神经元的传导速度估计值。碰撞测试包括以交替方式向外侧下丘脑和腹侧被盖区输送成对的脉冲。随着脉冲间隔的增加，双脉冲刺激的行为有效性突然增加，然后在更长的脉冲对间隔时趋于平稳。在6名受试者中，观察到突然上升的C-T间隔范围为1.0至3.0毫秒。使用类似的范式估计不应期，但两个脉冲都通过同一电极施加。恢复首先在大于0.4 - 0.6毫秒的脉冲对间隔时明显。通过将电极间距离除以碰撞间隔与不应期之间的差值来确定每个受试者的传导速度；获得了1.0 - 4.5米/秒的范围，这些值与报道的儿茶酚胺能纤维的传导速度不一致。有人提出，MFB中脑刺激奖励的底物由小的、有髓鞘的、非儿茶酚胺能纤维组成。
