OCULAR DOMINANCE COLUMN DEVELOPMENT - STRABISMUS CHANGES THE SPACING OF ADJACENT COLUMNS IN CAT VISUAL-CORTEX

To investigate the role of visual experience for the gross layout of o cular dominance (OD) columns in the visual cortex, I compared the resp ective patterns in normally raised and strabismic cats. OD domains wer e visualized by (1) transneuronal labeling of the afferents from the l eft or right eye with intraocular H-3-proline injections or (2) C-14-2 -deoxyglucose autoradiography after monocular visual stimulation in aw ake animals. To obtain the complete pattern of OD columns, flat-mount sections were prepared from the unfolded cortical hemispheres. Elimina ting correlated activity between the two eyes by making the animals st rabismic influenced the gross layout of the OD domains. In area 17, OD domains become more sharply delineated than in normal animals and spa ced more widely. Spatial frequency analyses revealed a mean spacing of adjacent columns of 1100-1300 mu m in strabismic and of 800-1000 mu m in normal cats. In area 18, the spacing of the ocular dominance domai ns is larger than in area 17 for both normal and strabismic cats (1500 -1650 mu m), but little influenced by strabismus. These results indica te that in area 17 decreased correlation of activity between the eyes alters the periodicity of OD columns. In addition, these observations suggest that not only the segregation of afferents into distinct colum ns but also the final expression of the columnar grid is influenced by visual experience, and in particular by the temporal patterning of ne ural activity. This is further evidence for the hypothesis that the de velopment of OD columns is governed by activity-dependent self-organiz ing principles.