AN INVESTIGATION OF THE DEVELOPMENT OF OCULAR DOMINANCE AND ORIENTATION COLUMNS IN CAT STRIATE CORTEX USING 2-DEOXYGLUCOSE

Neurophysiological studies on the striate cortex of immature cats have indicated that although oriented neurones occur they are broadly tuned and have a more imprecise columnar organization. Similarly transneuronal autoradiography reveals an initially incomplete segregation of the geniculo-cortical afferents. We have used 2-deoxyglucose autoradiography to examine the development of columnar metabolic label in the striate cortex of normal and binocularly deprived kittens following either monocular stimulation or stimulation with fixed orientations. In normal animals, both orientation and ocular dominance columns achieve an adultlike pattern at 5–6 weeks of age and indications of periodic labelling in both stimulus conditions are first apparent at 3 weeks. After stimulation with fixed orientations at 3 weeks, discrete foci of increased labelling are seen in layer IV; it is only in older animals that a full columnar pattern appears. At 3 weeks, ocular dominance columns extend through all cortical layers both ipsilateral and contralateral to the stimulated eye; the columns become more regular in older animals. Binocular deprivation appears to inhibit the formation of orientation columns as defined by de-oxyglucose autoradiography; only in one 35 day old cat was there an indication of columnar labelling. Ocular dominance columns were less affected by binocular deprivation; at both 5 weeks and 3 months there was definite periodic label although the distribution in the younger animal was less regular than in a comparable normal animal.