Zebra danio embryos have a sense of rhythm, and are capable of remembering a pattern of beats according to a study published in a recent issue of the journal Nature.
The study by Germn Sumbre and coauthors exposed zebrafish (Danio rerio) embryos to a series of regular light pulses, continuing to observe the embryos after the light pulses were switched off.
The authors observed the baby zebrafish to wiggle their tails with each light pulse; the fish were also observed to show activity in the optic tectum, a section of the brain that process visual information.
When the researchers turned off the lights, the zebrafish embryos continued wiggling their tails and showing signs of brain activity in time with the rhythm for a period of 20 seconds.
This ability of the zebrafish embryo to anticipate may help them elude predators, according to the researchers.
For more information, see the paper: Sumbre, G, A Muto, H Baier and M-M Poo (2008) Entrained rhythmic activities of neuronal ensembles as perceptual memory of time interval. Nature 456, pp. 102"106.