Journal of Neuroscience, Vol 10, 2931-2939, Copyright © 1990 by Society for Neuroscience
Neuronal development and migration in explant cultures of the adult canary forebrain
SA Goldman
Department of Neurology, Cornell University Medical College, New York, New York 10021.
The vocal control nucleus (HVc) of the songbird forebrain undergoes
neurogenesis in adulthood, as ventricular zone precursor cells divide, and
their daughter cells migrate into the subjacent forebrain and differentiate
into neurons. A procedure is now described by which the migration and
development of these new neurons can be directly observed in vitro, in
explant cultures of the adult canary forebrain. Cultured explants have
yielded extensive outgrowth of new neurons from 2 neurogenic regions of the
adult songbird brain: the HVc and its adjacent dorsomediocaudal
neostriatum. Immunocytochemically identified neurons were determined by
3H-thymidine autoradiography to have been newly generated in vivo, in the
days preceding explantation. These cells were immunoreactive for a variety
of neuron-selective antigens, including MAP-1B, MAP-2, neuron-specific
enolase, synaptic vesicle protein-2, N-CAM, and the tetanus toxin and A2B5
ligands. Combined immunostaining and autoradiography of cultures derived
from HVcs exposed to 3H-thymidine in vivo revealed a population of newly
generated, MAP-2/3H-thymidine-positive neurons. The neurons identified in
these adult explant outgrowths comprised new, recently generated
postmitotic cells which had arisen in the neostriatal ventricular zone and
were in the early stages of their parenchymal migration at the time of
tissue explantation. Accordingly, nonneurogenic control regions, including
the anterior hyperstriatum, cerebellum, and optic tectum, did not display
neuronal outgrowth in culture. Only forebrain regions exhibiting
neurogenesis in vivo manifested neuronal outgrowth and maturation in vitro.