Abstract: PURPOSE: In adults, depriving one eye for a short period of time increases its predominance in subsequent binocular vision, reflecting a form of homeostatic plasticity. Physiological and behavioral evidence suggests that this form of monocular deprivation does not alter monocular excitability, but rather alters binocular interactions by modulating inhibition between the eyes. Here, we investigated whether the plasticity in monocular deprivation could be modulated by changes in interocular suppression.
METHODS: Before monocular deprivation, interocular suppression was manipulated by a modulational binocular rivalry, which contained 3 contrast change conditions (ramping up, ramping down, and constant control) in the to-be-deprived eye, while the other eye held constant. Eye dominance change was measured by binocular rivalry at the beginning and the end of the whole experiment.
RESULTS: Changes in monocular contrast in the to-be-deprived eye modulated the strength of interocular suppression, and preceding changes of monocular contrast attenuated the dominance increase of the deprived eye in monocular deprivation. Furthermore, the degree of interocular suppression change within modulational rivalry was positively correlated with the degree of subsequent plasticity attenuation in monocular deprivation.
CONCLUSIONS: The plasticity in monocular deprivation is plastic, and can be modulated through changes in interocular suppression. Our study further supported the role of interocular suppression in visual plasticity, and provided a novel way of plasticity modulation.

Key words: monocular deprivation, neural plasticity, metaplasticity, binocular rivalry