EFFECTS OF EARLY DISCORDANT BINOCULAR VISION ON THE POSTNATAL-DEVELOPMENT OF PARVOCELLULAR NEURONS IN THE MONKEY LATERAL GENICULATE-NUCLEUS

The effects of early discordant binocular vision on the fidelity of si gnal transfer in parvocellular neurons of the lateral geniculate nucle us (LGN) were investigated in rhesus monkeys reared with ocular misali gnment (strabismus). Unilateral convergent strabismus (esotropia) was surgically induced in four infant monkeys between 20 and 30 days of ag e and the animals were reared in a normally lighted environment until they were adults. Extracellular microelectrode recordings were made in individual units of anesthetized and paralyzed subjects. Drifting sin usoidal gratings were used as visual stimuli. Within-unit comparisons of the LGN action potentials (LGN output) and S potentials (retinal in put) were performed to determine the accuracy of signal transfer in th e LGN, Contrary to the previous findings in the cat LGN, the signal tr ansfer characteristics of parvocellular units in strabismic mon keys w ere normal regardless of stimulus spatial frequency, temporal frequenc y, or contrast. The differences between cats and monkeys in LGN circui try and the relative maturity of the central visual pathway at the ons et of strabismus may have contributed to the apparent species differen ces in the functional development of the LGN.