Abstract
Both adaptation and perceptual learning can change how we perceive the visual environment, reflecting the plasticity of the visual system. Our previous work has attempted to investigate the interaction between the two aspects of visual plasticity. One of the main findings is that multiple days of repeated motion adaptation attenuates motion aftereffect (MAE), which is explained by habituation to the motion adapter. Interestingly, there is little transfer of habituation effect to the untrained adapter which differed from the trained one in the features including retinotopic location, spatiotopic location and motion direction. Research on visual perceptual learning has suggested that the transfer of learning effect can vary according to the features tested. Since features are processed in different neural loci along the visual pathways, probing the key features that determine the transfer of habituation in repeated motion adaptation may help disclose the underlying neural mechanisms for this phenomenon. Participants were trained to adapt to a motion adapter for 8 days. Before and after training, the MAE of the trained and an untrained adapter were tested. In three experiments, we examined the role of retinotopic location, spatiotopic location, and motion direction on the transfer of habituation, respectively. In each experiment, only one of the features was kept the same for the trained and untrained conditions. Suppose we can observe a significant transfer of habituation effect when one feature is rendered the same for the two conditions, but no transfer when it differs across the conditions. Then that feature would be the key determinant for the transfer. We found that the habituation effect transferred across both the retinotopic and spatiotopic locations as long as the adapting direction remained the same, suggesting that the habituation of motion adaptation is likely related to the plasticity of direction-selective neurons with large receptive fields.