Time course of the development of motor behaviors in the zebrafish embryo

Abstract

The development and properties of locomotor behaviors in zebrafish embryos raised at 28.5°C were examined. When freed from the chorion, embryonic zebrafish showed three sequential stereotyped behaviors: a transient period of alternating, coiling contractions followed by touch‐evoked rapid coils, then finally, organized swimming. The three different behaviors were characterized by video microscopy. Spontaneous, alternating contractions of the trunk appeared suddenly at 17 h postfertilization (hpf), with a frequency of 0.57 Hz, peaked at 19 hpf at 0.96 Hz, and gradually decreased to <0.1 Hz by 27 hpf. Starting at 21 hpf, touching either the head or the tail of the embryos resulted in vigorous coils. The coils accelerated with development, reaching a maximum speed of contraction before 48 hpf, which is near the time of hatching. After 27 hpf, touching the embryos, particularly on the tail, could induce partial coils (instead of full coils). At this time, embryos started to swim in response to a touch, preferentially to the tail. The swim cycle frequency gradually increased with age from 7 Hz at 27 hpf to 28 Hz at 36 hpf. Lesions of the central nervous system rostral to the hindbrain had no effect on the three behaviors. Lesioning the hindbrain eliminated swimming and touch responses, but not the spontaneous contractions. Our observations suggest that the spontaneous contractions result from activation of a primitive spinal circuit, while touch and swimming require additional hindbrain inputs to elicit mature locomotor behaviors. © 1998 John Wiley & Sons, Inc. J Neurobiol 37: 622–632, 1998

Nicotinic Receptors Mediate Changes in Spinal Motoneuron Development and Axonal Pathfinding in Embryonic Zebrafish Exposed to Nicotine

“…Zebrafish embryos can perceive tactile stimulation beginning at 27 hpf; this is characterized by a bend of the musculature away from the stimulus (Granato and Nusslein-Volhard, 1996;Ribera and Nusslein-Volhard, 1998;Saint-Amant and Drapeau, 1998). By 36 -42 hpf, embryos swim vigorously in response to tactile stimulation.…”

Slow degeneration of zebrafish Rohon‐Beard neurons during programmed cell death

“…For example, embryos homozygous for mutations affecting motoneurons have difficulty hatching . Removal of the hindbrain that contains the Mauthner cells eliminates the behavioral response to touch (Saint-Amant and Drapeau, 1998). narrowminded mutants that lack RBs (Artinger et al, 1999) and macho mutants that have a reduced touch response because of a reduced sodium current in RBs (Svoboda et al, 2001) have difficulty hatching (K.B.…”

Amino acid variations resulting in functional and nonfunctional zebrafish P2X1 and P2X5.1 receptors

“…To examine this issue at the zebrafish neuromuscular junction, we assessed synaptic communication in the absence of P2X signaling behaviorally by assaying the ability of embryos to swim following morpholino-mediated blockade of zP2X 5.1 expression. A swim was stimulated in control embryos by touching the head or tail with a pair of forceps to induce touch-evoked escape contractions and swimming [36]. Touch was found to induce similar responses in zP2X 5.1 morpholino-injected embryos (Fig.…”