Abstract: An important goal in neuroscience is to understand and control brain plasticity, with ocular dominance plasticity being a particularly active area of research. Ocular dominance refers to the phenomenon in which one eye exhibits functional superiority to the other. One extreme pathological manifestation of ocular dominance is amblyopia. Ocular dominance is not fixed but can shift in response to visual experiences, which demonstrates its plasticity. Classic neuroscience research suggests that ocular dominance plasticity is most pronounced during the critical period of development, yet adult’s ocular dominance remains relatively stable. By contrast, recent studies on short-term monocular deprivation have shown that adults retain a certain degree of ocular dominance plasticity. To date, pursuing more effective methods for reshaping adult’s ocular dominance remains to be an active research topic, which is crucial for treating adult amblyopia.
Recent studies have highlighted that top-down attention, in addition to visual input, can also modulate ocular dominance. These findings provide a novel theoretical basis for refining the traditional monocular deprivation paradigm that relies solely on visual input. While some studies have started to explore the role of attention in modulating the short-term monocular deprivation effects, research in this direction remains limited. Notably, brain plasticity can be regulated by reward, e.g. combining reward with training can enhance learning and facilitate neurorehabilitation. Building on these insights, integrating rewards with short-term monocular deprivation may offer a novel and effective approach to promoting ocular dominance plasticity in adults. To date, it remains unclear whether reward can modulate short-term monocular deprivation effects, and the underlying mechanisms require further elucidation.
To address these issues, we will propose three studies that employ an innovative short-term monocular deprivation paradigm incorporating rewards, alongside the use of behavioral, EEG, fMRI, and TMS techniques, to systematically investigate the influences of reward on short-term monocular deprivation effects and its underlying cognitive-neural mechanisms.
Specifically, study 1 will seek to investigate whether reward could enhance the effects of short-term monocular deprivation. This study will be composed of two experiments. Experiment 1 will examine the impact of reward on the short-term monocular deprivation effect by measuring perceptual ocular dominance, while Experiment 2 will employ EEG technology to assess the role of reward in modulating the neural effect of short-term monocular deprivation. Study 2 will aim to elucidate the potential mechanisms through which reward modulate the short-term monocular deprivation effect. This study will consist of three experiments. Experiment 3 will investigate whether task-irrelevant reward (i.e., reward not dependent on attention) can regulate the short-term monocular deprivation effect, thereby shedding light on the role of attention in the modulation of monocular deprivation effects by reward. Experiments 4 and 5 will integrate fMRI and TMS techniques to uncover the causal mechanisms by which reward influences the short-term monocular deprivation effect. Study 3 will evaluate whether the introduction of reward in short-term monocular deprivation training may produce better treatments for adult amblyopia. The study plans to recruit two groups of amblyopic patients: one group will undergo traditional short-term monocular deprivation training, while the other will receive reward-based short-term monocular deprivation training. Visual acuity, stereoscopic vision, and perceptual ocular dominance will be assessed pre- and post-training to assess the efficacy of the reward-based training.
This study elucidates how bottom-up visual input (monocular deprivation) and top-down cognitive regulation (reward) collaboratively modulate ocular dominance, thereby advancing the understanding of short-term ocular dominance plasticity. Furthermore, comprehending this interaction will deepen our insight into how the brain adapts its functions in response to both external stimuli and internal cognitive states, enriching our broader understanding of human vision and brain plasticity. Additionally, by integrating reward-based methods with short-term monocular deprivation, this study holds the potential to offer a more effective approach for reshaping adult ocular dominance, thereby contributing to the development of innovative treatment strategies for adult amblyopia.

Key words: reward, ocular dominance, plasticity, monocular deprivation, attention