Eaton R C, Emberley D S
Department of Biology, University of Colorado, Boulder 80309.
J Exp Biol. 1991 Nov;161:469-87. doi: 10.1242/jeb.161.1.469.
Fishes use the Mauthner-initiated C-start for short-latency evasion of predators. C-starts consist of a sudden turn (stage 1) and a rapid acceleration (stage 2). We analyzed high-speed ciné films of goldfish C-starts elicited by dropping a ball into the water. It was previously thought that stage 1 angle does not vary concomitantly with the angle of the threatening stimulus relative to the position of the fish. We found, however, a significant inverse relationship between the direction of the impact of the ball and the angle turned by the end of stage 1. When starting near a wall, or when its usual trajectory was blocked by a wall, the fish used an escape route that was not predictable from the stimulus angle. The fish did not appear to correct its trajectory if it began to turn towards the ball. This behavioral evidence supports the previous notion that the underlying neural command is ballistic and does not use sensory information from the stimulus once the movement begins. If this is so, the fish probably utilizes information on obstacle location in the interval leading up to the trigger stimulus.
鱼类利用由莫特纳神经元引发的C形启动反应来短时间内躲避捕食者。C形启动反应包括一个突然转向（阶段1）和一次快速加速（阶段2）。我们分析了通过向水中投放小球引发金鱼C形启动反应的高速电影胶片。之前人们认为阶段1的转向角度与威胁刺激相对于鱼的位置的角度并不同步变化。然而，我们发现小球撞击方向与阶段1结束时鱼转过的角度之间存在显著的反比关系。当鱼在靠近墙壁处开始启动，或者其正常轨迹被墙壁阻挡时，鱼会采用一种从刺激角度无法预测的逃生路线。如果鱼开始转向小球，它似乎不会纠正其轨迹。这一行为证据支持了之前的观点，即潜在的神经指令是一次性的，并且一旦运动开始就不会使用来自刺激的感官信息。如果是这样，鱼可能在触发刺激之前的这段时间内利用了关于障碍物位置的信息。
