The zebrafish has recently assumed a central position
in the study of vertebrate development. Numerous studies
of other fish have shown that their central nervous systems,
and especially their visual systems, continue to add new
neurons throughout life, which is probably related to their
abilities to regenerate axons and whole nervous tissue.
Retinal neurogenesis had not been examined in adult zebrafish,
and two reports concluded that the optic tectum ceased
neurogenesis early in life, so the question arose whether
the zebrafish was anomalous in this regard. We labeled
embryonic (24- and 48-h postfertilization) and adult zebrafish
with the thymidine analog, bromo-deoxyuridine, and, after
short and long survivals, examined the retina and brain
for labeled cells. They were abundant in both the optic
tectum and the retina. Although the rate of retinal growth
slows considerably between embryonic and adult stages,
the patterns of neurogenesis in both the embryo and the
adult are similar to those described in other fish, so
these “fish-specific” features of general interest
can justifiably be studied in zebrafish.
The effects of temperature on the proxies of visual detection of Danio rerio larvae: observations from the optic tectum
