IRCP
Pacific Coral Reef Institute
EPHE

Lateralization Process by Coral Reef Fish – IRCP Grant

Having got an IRCP grant in 2011, Rynae G. Lanyon, from the University of South Pacific (USP) published her third article on fish brain in Animal Behavior journal, in collaboration with seven other scientists. After a work on the visual abilities of coral reef fish larvae, this is the lateralization process used in the visual recognition that is explored here:

In vertebrates, brain functional asymmetries are widespread and are known to increase brain performance. For numerous species, the left and the right sides of the brain present distinct role in information perception and in response emission which seems to be important in sensory processing. Some fish species, such as cichlids and zebrafish are known to have brain asymmetries. However, little information is available on brain lateralization in coral reef fishes and the impact this could have during the recruitment phase.

In this study, soldierfish Myripristis pralinia has been used at the larval and juvenile stage in order to test the role of both left and right telencephalic hemisphere in the perception of visual cues. The experiments conducted by the research team were done to see whether there was a difference in visual perception between the left and the right hemispheres during the larval development. Left of right telencephalon was ablated from larvae and juveniles of M. pralinia and their ability to visually recognize conspecific was then tested. Individuals were placed in a 3 compartments aquarium (divided by transparent glass) to test their ability to visually recognize conspecifics. The Larvae with the ablation of either the right or left telencephalic hemisphere lost the attraction towards conspecific cues. In contrast, juveniles with the ablation of the right (but not left) telencephalic hemisphere still displayed a preference towards conspecific visual cues. These results suggest the left telencephalic hemisphere is responsible for the lateralization process used in the visual recognition of coral reef fish juveniles.

The two-choice aquarium (60 x12 cm and 10 cm high) used to behaviourally assess visual recognition in larval and juvenile M. pralinia. The tested fish (after ablation) is put in the central part of the aquarium and its behavior recorded during 1 minute. Is the fish able to recognize fishes of its species and other fishes?

The two-choice aquarium (60 x12 cm and 10 cm high) used to behaviourally assess visual recognition in larval and juvenile M. pralinia. The tested fish (after ablation) is put in the central part of the aquarium and its behavior recorded during 1 minute. Is the fish able to recognize fishes of its species and other fishes?

Different parts of a fish brain

Different parts of a fish brain

The determinism of lateralized perception of conspecifics during fish ontogeny may be a consequence of genetic factors, linked with the metamorphosis processes and/or environmental factors such as predation at recruitment.

Roux N., Duran E., Lanyon R.G., Frédérich B., Berthe C., Besson M., Dixson D.L., Lecchini D., 2016.Brain lateralization involved in visual recognition of conspecifics in coral reef fish at recruitment. Animal Behaviour, vol. 117: 3-8. IF: 3.4

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