Background: This study examined condition-dependent electroencephalography (EEG) changes under progressive degradation of visual and tactile information. Methods: Using a controlled visual–tactile paradigm, we systematically manipulated visual degradation and tactile impairment at multiple levels and analyzed time–frequency activity and P300 responses. Results: The results showed condition-dependent changes in oscillatory activity and P300 amplitude across graded visual–tactile degradation conditions. In several conditions, degradation in one modality was accompanied by increased neural responses in the other modality. However, this pattern was not monotonic: stronger responses were observed under some moderate degradation combinations, whereas responses were reduced under severe dual-modal degradation. Conclusions: In addition, the relative balance between visual-task and tactile-task responses varied across conditions, suggesting flexible but condition-dependent changes in modality weighting rather than a fixed hierarchy between modalities. Overall, these findings are consistent with graded neural adaptation under visual–tactile uncertainty, but they do not by themselves establish a specific causal mechanism of sensory reallocation.
Yang et al. (Tue,) studied this question.