The Journal of Neuroscience, May 1, 1998, 18(9):3404-3415
Patchy Distribution of NMDAR1 Subunit Immunoreactivity in
Developing Visual Cortex
Christopher
Trepel1,
Kevin R.
Duffy1,
Victor D.
Pegado1, and
Kathryn M.
Murphy1, 2
McMaster University, Departments of 1 Psychology and
2 Biomedical Sciences, Hamilton, Ontario L8S 4K1, Canada
Development of ocular dominance columns is dependent on patterned
retinal activity, and yet patterned activity alone cannot explain all
aspects of cortical column development. Features intrinsic to the
cortex have been proposed to interact with activity to guide the
patterning of cortical columns (), and the NMDA
receptor, because of its role in experience-dependent plasticity, is an
obvious candidate. Using immunohistochemical techniques, we found a
transiently patchy distribution of the NMDA receptor 1 (NMDAR1) subunit
in kitten visual cortex. Regularly spaced patches of
NMDAR1-immunoreactive neurons were found at the top of the cortical
plate in the developing visual cortex at 2 weeks of age. At 4-5 weeks
of age, the radial extent of the NMDAR1 patches spanned the
supragranular layers, and by 12 weeks of age, this nonuniform pattern
of NMDAR1 immunostaining was no longer apparent. Monocular visual
experience prevented the expression of the NMDAR1 patches, but just
4 d of subsequent binocular visual experience was sufficient to
promote expression of the patches. Furthermore, the NMDAR1 patches
tended to be associated with the borders of ocular dominance columns.
These results suggest that the degree of plasticity associated with
NMDA-mediated mechanisms is elevated in local regions across the
tangential extent of the visual cortex and that the NMDAR1 patches may
participate in sculpting the overall arrangement of visual cortical
columns.
Key words:
cortical column; development; excitatory amino acid
receptors; visual cortex; NMDA; ocular dominance
Copyright © 1998 Society for Neuroscience 0270-6474/98/1893404-12$05.00/0