The Journal of Neuroscience, February 1, 2002, 22(3):825-831
Experience Affects Recruitment of New Neurons But Not Adult
Neuron Number
Linda
Wilbrecht,
Alex
Crionas, and
Fernando
Nottebohm
Laboratory of Animal Behavior, The Rockefeller University, New
York, New York 10021
It is not known whether the addition of new neurons to the high
vocal center (HVC) of juvenile zebra finches permits vocal learning or
is the consequence of it. To tease apart these two, we performed
surgery on 26-d-old juveniles. The operations were removal of both
cochleae and unilateral or bilateral denervation of the syrinx. Ability
to imitate a tutor song was little affected by unilateral syringeal
denervation but was severely hindered by bilateral denervation or
deafening. Recruitment of new HVC neurons was studied by injecting
BrdU, a cell birth marker, on post-hatching days 61-65 and killing the
animals 30 d later. Deafening or bilateral denervation did not
alter the number of BrdU-labeled neurons in HVC, but unilateral
denervation nearly doubled this number in the intact side. This
doubling was transient, was blocked by deafening, and was not seen in
birds that received BrdU injections earlier or later in vocal ontogeny.
The adult number of HVC neurons was not affected by any of our surgical
procedures. Apparently experience does not affect the total number of
neurons in adult HVC, but some kinds of experience can, during narrowly
defined times, influence the recruitment of new HVC neurons.
Key words:
song learning; neurogenesis; BrdU; unilateral
denervation; sensitive period; syrinx
Copyright © 2002 Society for Neuroscience 0270-6474/02/223825-07$05.00/0