Novelty Detection in Electric Fish

对新刺激的行为反应一般有三种：惊吓、唤醒和定向。惊吓反应是由短暂刺激（通常是视觉或听觉刺激）引起的一组短潜伏期肌肉收缩。惊阈值远远大于动物的检测阈值是其特征。唤醒行为以一系列身体反应为特征。尽管比惊吓行为更微妙，但有效刺激和反应都具有唤醒的普遍性，这使得对新颖性检测中涉及的单个神经元素的研究存在问题。虽然定向反应在鱼类中还没有很好地定义，但脉冲型弱电鱼的新奇反应最适合哺乳动物的这一类别。这种新奇的反应是驱动鱼的电器官的起搏器的短暂加速。它是由接近检测阈值的微小刺激变化引起的，是一种微妙而可靠的行为，具有非爆炸性、不应期短、单一效应途径。脉冲型弱电鱼的新奇反应非常适合神经生理学分析，并允许同时测量行为和神经反应。兰迪·泽里克博士将继续研究电鱼的新奇探测。这项工作意义重大，因为它将使我们更好地理解神经系统如何区分新奇的和背景的感觉输入。//

There are three general classes of behavioral responses to a novel stimulus: startle, arousal and orientation. The startle response is a short latency set of muscular contractions induced by a brief stimulus, typically visual or acoustic. It is characteristic for the startle threshold to be much greater than the animal's detection threshold. Arousal behavior is characterized by a suite of physical responses. Although more subtle than startle behavior, both the effective stimuli and the responses are quite general with arousal, making investigation of the individual neural elements involved in novelty detection problematic. Although orienting responses have not been well defined in fish, the novelty response of pulse-type weakly electric fish fits best into this category as defined for mammals. The novelty response is a transient acceleration of the pacemaker which drives the fish's electric organ. Elicited by small stimulus changes near detection threshold, it is a subtle but reliable behavior which is not explosive, has a short refractory period, and involves a single effector pathway. The novelty response of pulse-type weakly electric fish is well suited to neurophysiological analysis and permits simultaneous measurement of behavioral and neural responses. Dr. Randy Zelick will continue his work on novelty detection in electric fish. This work is significant since it will give us a better understanding of the means by which the nervous system distinguishes novel from background sensory input. //