Development of orientation columns in cat striate cortex revealed by 2-deoxyglucose autoradiography.

In the striate cortex of adult monkeys and cats, both electrophysiology1-3 and the 2-deoxyglucose autoradiographic technique of Sokoloff4-8 suggest that neurones are arranged in functional columns or slabs that run through the full thickness of the cortex, each column containing cells with a preference for a particular orientation of line or edge in the visual field. There is disagreement, however, concerning the organization of visual cortex in very young animals and the role of visual experience in cortical development. Orientation-selective neurones clearly exist in immature cat cortex, but reports differ on their frequency, angular selectivity and degree of columnar organization (see ref. 9 for review). We have used 2-deoxyglucose autoradiography to investigate the development of cat striate cortex. This technique reveals the spatial distribution of activity in populations of neurones and should therefore provide information about how the columnar pattern develops and whether its maturation depends on visual stimulation. We report here that in normal animals, periodic metabolic labelling around layer IV was first clearly observed at 21 days of age and by 35 days the pattern had become truly columnar; in a matched series of animals deprived of normal pattern vision no differential label was observed except for weak periodicity in a single 35-day-old animal. These results suggest that cat striate cortex is immature at the time of eye-opening and that visual experience is crucial for normal maturation.