Bishop Benjamin H, Spence-Chorman Nathan, Gahtan Ethan
Department of Psychology, Humboldt State University, 1 Harpst Street, Arcata, CA 95521, USA.
Department of Psychology, Humboldt State University, 1 Harpst Street, Arcata, CA 95521, USA
J Exp Biol. 2016 Dec 15;219(Pt 24):3981-3987. doi: 10.1242/jeb.147124. Epub 2016 Oct 24.
Escape behaviors have been studied in zebrafish by neuroscientists seeking cellular-level descriptions of neural circuits but few studies have examined vertical swimming during escapes. We analyzed three-dimensional swimming paths of zebrafish larvae during visually-evoked and auditory-evoked escapes while the fish were in a cubical tank with equal vertical and lateral range. Visually evoked escapes, elicited by sudden dimming of ambient light, consistently elicited downward spiral swimming (dives) with faster vertical than lateral movement. Auditory taps also elicited rapid escape swimming with equivalent total distance traveled but with significantly less vertical and more lateral movement. Visually evoked dives usually ended with the zebrafish hitting the bottom of the 10 cm tank. Therefore, visually evoked dives were also analyzed in a tubular tank with 50 cm of vertical range, and in most cases larvae reached the bottom of that tank during a 120 s dimming stimulus. Light-evoked spiral diving in zebrafish may be an innate defense reflex against specific predation threats. Since visual and auditory escapes are initially similar but dives persist only during visual escapes, our findings lay the groundwork for studying a type of decision-making within zebrafish sensorimotor circuits.
神经科学家们通过研究斑马鱼的逃逸行为来寻求对神经回路的细胞水平描述，但很少有研究考察逃逸过程中的垂直游动。我们分析了斑马鱼幼体在视觉诱发和听觉诱发逃逸过程中的三维游动路径，实验中鱼处于一个垂直和横向范围相等的立方体水箱中。视觉诱发逃逸由环境光的突然变暗引发，始终会引发向下的螺旋游动（下潜），垂直方向的移动比横向移动更快。听觉敲击也会引发快速的逃逸游动，游动的总距离相当，但垂直移动明显更少，横向移动更多。视觉诱发的下潜通常以斑马鱼撞到10厘米水箱的底部结束。因此，我们还在一个垂直范围为50厘米的管状水箱中分析了视觉诱发的下潜，在大多数情况下，幼体在120秒的变暗刺激过程中到达了那个水箱的底部。斑马鱼中光诱发的螺旋下潜可能是针对特定捕食威胁的一种先天防御反射。由于视觉和听觉逃逸最初相似，但下潜仅在视觉逃逸过程中持续存在，我们的研究结果为研究斑马鱼感觉运动回路中的一种决策类型奠定了基础。
