Long-term exercise training reduced the sound-induced flash illusion in multisensory illusions owing to the cerebellum.

Sound-induced flash illusion (SiFI) is an auditory-dominant multisensory illusion that can be used to assess multisensory integration. Although previous studies have shown that one-time intervention exercise training does not significantly affect SiFI, the long-term improvement of SiFI with exercise training remains controversial. In the present study, the classical SiFI paradigm was used to investigate the effects of long-term exercise training on the SiFI. Differences in SiFI among the skill exercise, physical exercise, and control groups were also assessed. The results showed that SiFI was lower in both the skill group and the physical group than in the control group (Experiment 1), and the skill group had a lower SiFI than the control group because the skill group had a finer temporal binding window of multisensory integration (Experiment 2). In addition, previous studies have shown that brain plasticity in athletes of open skill exercises is predominantly in the cerebellum and that exercise skill learning is associated with cerebellar neuroplasticity. Therefore, we used transcranial direct current stimulation (tDCS) to modulate the cerebellum to examine whether the cerebellum was involved in SiFI (Experiment 3). The results showed that the cerebellum was involved in the SiFI, and the reduction in the SiFI in the skill group was due to the increase in developed cerebellar function resulting from long-term skill training. These results suggest that long-term skill exercise training is effective at preventing SiFI, and the present study provides empirical support for intervention training in the area of multisensory integration.