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Fusion of locomotor maneuvers, and improving sensory capabilities, give rise to the flexible homing strikes of juvenile zebrafish.

Westphal RE, O'Malley DM - Front Neural Circuits (2013)

Bottom Line: At 5 days post-fertilization and 4 mm in length, zebrafish larvae are successful predators of mobile prey items.Neomycin ablation of lateral line hair cells reduced the accuracy of strikes and overall feeding rates, especially when neomycin-treated larvae and juveniles were placed in the dark.Darkness by itself reduced the distance from which strikes were launched, as visualized by infrared imaging.

View Article: PubMed Central - PubMed

Affiliation: Department of Natural Sciences, North Shore Community College Lynn, MA, USA.

ABSTRACT
At 5 days post-fertilization and 4 mm in length, zebrafish larvae are successful predators of mobile prey items. The tracking and capture of 200 μm long Paramecia requires efficient sensorimotor transformations and precise neural controls that activate axial musculature for orientation and propulsion, while coordinating jaw muscle activity to engulf them. Using high-speed imaging, we report striking changes across ontogeny in the kinematics, structure and efficacy of zebrafish feeding episodes. Most notably, the discrete tracking maneuvers used by larval fish (turns, forward swims) become fused with prey capture swims to form the continuous, fluid homing strikes of juvenile and adult zebrafish. Across this same developmental time frame, the duration of feeding episodes become much shorter, with strikes occurring at broader angles and from much greater distances than seen with larval zebrafish. Moreover, juveniles use a surprisingly diverse array of motor patterns that constitute a flexible predatory strategy. This enhances the ability of zebrafish to capture more mobile prey items such as Artemia. Visually-guided tracking is complemented by the mechanosensory lateral line system. Neomycin ablation of lateral line hair cells reduced the accuracy of strikes and overall feeding rates, especially when neomycin-treated larvae and juveniles were placed in the dark. Darkness by itself reduced the distance from which strikes were launched, as visualized by infrared imaging. Rapid growth and changing morphology, including ossification of skeletal elements and differentiation of control musculature, present challenges for sustaining and enhancing predatory capabilities. The concurrent expansion of the cerebellum and subpallium (an ancestral basal ganglia) may contribute to the emergence of juvenile homing strikes, whose ontogeny possibly mirrors a phylogenetic expansion of motor capabilities.

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Aborted vs. successful feeding episodes of larval zebrafish. Tracking maneuvers appear similar between successful feeding episodes (upper panel) and aborted feeding episodes (lower panel). Both panels show the onset of tracking, orientation to the prey and a closing maneuver to the point where the larvae are very close and well oriented towards the Paramecium. While the larva successfully engulfs the Paramecium using a capture swim in the upper sequence, the aborted episode in the lower sequence shows a distinct turn that produces a large offset angle away from the prey item, ending the episode (the edge of the Petri dish is seen in the lower panel).
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Figure 10: Aborted vs. successful feeding episodes of larval zebrafish. Tracking maneuvers appear similar between successful feeding episodes (upper panel) and aborted feeding episodes (lower panel). Both panels show the onset of tracking, orientation to the prey and a closing maneuver to the point where the larvae are very close and well oriented towards the Paramecium. While the larva successfully engulfs the Paramecium using a capture swim in the upper sequence, the aborted episode in the lower sequence shows a distinct turn that produces a large offset angle away from the prey item, ending the episode (the edge of the Petri dish is seen in the lower panel).

Mentions: In some first feeding episodes, young larvae oriented and moved towards a nearby prey item, but did not consume it. Failed episodes resulted from both misses and, more frequently, aborted episodes, where items were tracked and approached, but no strike was launched. In comparing successful and aborted episodes (Figure 10), both showed larvae orienting via J-turns towards a Paramecium and approaching it, but in the aborted case (lower row), the larva abruptly turned away terminating the feeding episode. Table 1 provides a comparison of 19 successful and 19 aborted feeding episodes.


Fusion of locomotor maneuvers, and improving sensory capabilities, give rise to the flexible homing strikes of juvenile zebrafish.

Westphal RE, O'Malley DM - Front Neural Circuits (2013)

Aborted vs. successful feeding episodes of larval zebrafish. Tracking maneuvers appear similar between successful feeding episodes (upper panel) and aborted feeding episodes (lower panel). Both panels show the onset of tracking, orientation to the prey and a closing maneuver to the point where the larvae are very close and well oriented towards the Paramecium. While the larva successfully engulfs the Paramecium using a capture swim in the upper sequence, the aborted episode in the lower sequence shows a distinct turn that produces a large offset angle away from the prey item, ending the episode (the edge of the Petri dish is seen in the lower panel).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3675323&req=5

Figure 10: Aborted vs. successful feeding episodes of larval zebrafish. Tracking maneuvers appear similar between successful feeding episodes (upper panel) and aborted feeding episodes (lower panel). Both panels show the onset of tracking, orientation to the prey and a closing maneuver to the point where the larvae are very close and well oriented towards the Paramecium. While the larva successfully engulfs the Paramecium using a capture swim in the upper sequence, the aborted episode in the lower sequence shows a distinct turn that produces a large offset angle away from the prey item, ending the episode (the edge of the Petri dish is seen in the lower panel).
Mentions: In some first feeding episodes, young larvae oriented and moved towards a nearby prey item, but did not consume it. Failed episodes resulted from both misses and, more frequently, aborted episodes, where items were tracked and approached, but no strike was launched. In comparing successful and aborted episodes (Figure 10), both showed larvae orienting via J-turns towards a Paramecium and approaching it, but in the aborted case (lower row), the larva abruptly turned away terminating the feeding episode. Table 1 provides a comparison of 19 successful and 19 aborted feeding episodes.

Bottom Line: At 5 days post-fertilization and 4 mm in length, zebrafish larvae are successful predators of mobile prey items.Neomycin ablation of lateral line hair cells reduced the accuracy of strikes and overall feeding rates, especially when neomycin-treated larvae and juveniles were placed in the dark.Darkness by itself reduced the distance from which strikes were launched, as visualized by infrared imaging.

View Article: PubMed Central - PubMed

Affiliation: Department of Natural Sciences, North Shore Community College Lynn, MA, USA.

ABSTRACT
At 5 days post-fertilization and 4 mm in length, zebrafish larvae are successful predators of mobile prey items. The tracking and capture of 200 μm long Paramecia requires efficient sensorimotor transformations and precise neural controls that activate axial musculature for orientation and propulsion, while coordinating jaw muscle activity to engulf them. Using high-speed imaging, we report striking changes across ontogeny in the kinematics, structure and efficacy of zebrafish feeding episodes. Most notably, the discrete tracking maneuvers used by larval fish (turns, forward swims) become fused with prey capture swims to form the continuous, fluid homing strikes of juvenile and adult zebrafish. Across this same developmental time frame, the duration of feeding episodes become much shorter, with strikes occurring at broader angles and from much greater distances than seen with larval zebrafish. Moreover, juveniles use a surprisingly diverse array of motor patterns that constitute a flexible predatory strategy. This enhances the ability of zebrafish to capture more mobile prey items such as Artemia. Visually-guided tracking is complemented by the mechanosensory lateral line system. Neomycin ablation of lateral line hair cells reduced the accuracy of strikes and overall feeding rates, especially when neomycin-treated larvae and juveniles were placed in the dark. Darkness by itself reduced the distance from which strikes were launched, as visualized by infrared imaging. Rapid growth and changing morphology, including ossification of skeletal elements and differentiation of control musculature, present challenges for sustaining and enhancing predatory capabilities. The concurrent expansion of the cerebellum and subpallium (an ancestral basal ganglia) may contribute to the emergence of juvenile homing strikes, whose ontogeny possibly mirrors a phylogenetic expansion of motor capabilities.

Show MeSH
Related in: MedlinePlus