Burgess Harold A, Granato Michael
Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6058, USA.
J Exp Biol. 2007 Jul;210(Pt 14):2526-39. doi: 10.1242/jeb.003939.
The neural basis of behavioral choice in vertebrates remains largely unknown. Zebrafish larvae have a defined locomotor repertoire as well as a simple nervous system and are therefore an attractive vertebrate system in which to study this process. Here we describe a high-throughput system for quantifying the kinematics of motor events in zebrafish larvae in order to measure the initiation frequency of different maneuvers. We use this system to analyze responses to photic stimuli and find that larvae respond to changes in illumination with both acute responses and extended behavioral programs. Reductions in illumination elicit large angle turns, distinct from startle responses, which orient larvae toward the source of light. In continuing darkness, larvae are transiently hyperactive before adopting a quiescent state. Indeed, locomotor activity is controlled by the state of light or dark adaptation similar to masking phenomena in higher vertebrates where light directly regulates motor activity. We propose that regulation of motor activity by photic stimuli in zebrafish larvae serves a behavioral goal of maximizing exposure to well lit environments optimal for feeding.
脊椎动物行为选择的神经基础在很大程度上仍然未知。斑马鱼幼体具有明确的运动模式以及简单的神经系统，因此是研究这一过程的一个有吸引力的脊椎动物系统。在这里，我们描述了一种高通量系统，用于量化斑马鱼幼体运动事件的运动学，以便测量不同动作的起始频率。我们使用该系统分析对光刺激的反应，发现幼体对光照变化既有急性反应，也有延长的行为程序。光照减少会引发大角度转弯，这与惊吓反应不同，惊吓反应会使幼体朝向光源定向。在持续黑暗中，幼体在进入静止状态之前会短暂地过度活跃。实际上，运动活动受光适应或暗适应状态的控制，类似于高等脊椎动物中的掩蔽现象，在高等脊椎动物中，光直接调节运动活动。我们提出，斑马鱼幼体中光刺激对运动活动的调节服务于一个行为目标，即最大限度地暴露于最适合觅食的光照良好的环境中。
