[Binocular competitive mechanisms in the visual cortex in early developing kittens of monocular deprivation and...

Using contrast reversing square- wave gratings as stimuli the pattern visual evoked potentials (P-VEP) and pattern electroretinograms (P-ERG) were simultaneously recorded to determine the spatial frequency tuning curves for kittens of monocular deprivation (from 8th to 12th postnatal week) and reverse suture (from 12th to 15th postnatal week), as compared with those of normal kittens of the same age and adult cats. The results showed that in the range from spatial frequency 0.12 to 1.5 c/d the amplitudes of P-VEP responses driven respectively by the left and the right eyes in normal kittens were similar but clearly smaller than those driven binocularly. For kittens with one eye deprived, the P-VEP amplitudes driven by the deprived eye decreased markedly. In contrast, the P-VEP amplitudes driven by the undeprived eye increased significantly, while the P-VEP amplitudes driven by simultaneous stimulation of both eyes were intermediate between the two monocular responses. For the reversely sutured kittens, the P-VEP amplitudes driven by the formally deprived eye recovered to some extent, while the P-VEP amplitudes driven by the reversely sutured eye decreased, and their amplitudes tended to be quite close. The P-VEP amplitude driven by both eyes was the biggest. Neither such shift of spatial frequency tuning curves of the P-VEP in adult cats, nor such functional competition between the two eye in P-ERG responses during early development of kittens of monocular deprivation and reverse suture was found.(ABSTRACT TRUNCATED AT 250 WORDS)