An attempt to assess the effects of monocular deprivation and strabismus on synaptic efficiency in the kitten's visual cortex.

The relative effectiveness of the two eyes in exciting cells in the visual cortex was assessed, using both natural stimulation and electrical stimulation of the optic discs. It is is argued that supramaximal electrical stimulation of the optic nerve could possibly reveal 'subliminal' synaptic inputs even after monocular deprivation or artificial strabismus has caused a loss of natural input from that eye, if such 'silent' synaptic input still survives. However, in kittens monocularly deprived for various periods of time or made artificially strabismic, there was usually excellent agreement between the relative visual excitability in the two eyes and their relative electrical excitability. In one animal, monocularly deprived continuously until 23 weeks of age, we examined the effect of reversibly turning off signals from the normal eye by pressure blinding. There was no evidence of a very rapid return of sensitivity to either electrical or natural stimulation of the deprived eye.