The Journal of Neuroscience, March 1, 2000, 20(5):1922-1930
Cortical Cell Orientation Selectivity Fails to Develop in the
Absence of ON-Center Retinal Ganglion Cell Activity
Barbara
Chapman and
Imke
Gödecke
Center for Neuroscience, University of California, Davis,
California 95616
Neuronal activity is necessary for the normal development of visual
cortical cell receptive fields. When neuronal activity is blocked,
cortical cells fail to develop normal ocular dominance and orientation
selectivity. Patterned activity has been shown to play an instructive,
rather than merely permissive, role in the segregation of
geniculocortical afferents into ocular dominance columns. To test
whether normal patterns of activity are necessary to instruct the
development of cortical orientation selectivity, we studied ferrets
raised without ON-center retinal ganglion cell activity. The ON-center
blockade was produced by daily intravitreal injections of
DL-2-amino-4-phosphonobutyric acid (APB). Effects of this
treatment on the development of orientation selectivity in primary
visual cortex were assessed using extracellular electrode recordings
and optical imaging. In animals raised with an ON-center blockade
starting after visual cortical cells are visually driven but still
poorly tuned for orientation, cortical cell responsivity was
maintained, but no maturation of orientation selectivity was seen. No
recovery of orientation tuning was seen in animals treated with APB
during the normal period of orientation development and then allowed
several months of development without treatment. These results suggest
that patterns of neuronal activity carried in the separate ON- and
OFF-center visual pathways are necessary for the development of
orientation selectivity in visual cortical neurons of the ferret and
that there is a critical period for this development.
Key words:
visual cortex; activity; DL-2-amino-4-phosphonobutyric acid; ON-center pathway; development; ferret
Copyright © 2000 Society for Neuroscience 0270-6474/00/2051922-09$05.00/0