TEMPORAL DYNAMICS OF CONSOLIDATION AND TASK INTERFERENCE IN TACTILE PERCEPTUAL LEARNING

In visual perceptual learning, performing a secondary task immediately following an initial learning session induces interference, obstructing the consolidation of the first task. This interference typically diminishes if the second task is delayed by approximately one hour, suggesting the completion of the stabilization process. However, whether similar temporal dynamics exist in the tactile domain remains to be fully elucidated.
This study investigated tactile learning interference using the grating orientation task (GOT) in 34 right-handed healthy adults. Participants were grouped according to the delay between these two tasks, receiving the interference task either 15 min or 60 min after the initial learning. The learning task required vertical/horizontal discrimination, while the interference task required oblique discrimination. Thresholds for both vertical/horizontal and oblique orientations were measured at baseline (Pre) and 24 hours later (Post).
In the 15-min interval group, a two-way ANOVA revealed a significant interaction between time and task. Post-hoc tests showed that while thresholds for the oblique task significantly improved, the improvement in the vertical/horizontal task was significantly inhibited. In contrast, the 60-min interval group showed significant improvements in both tasks without a significant interaction, suggesting that the interference effect had subsided.
These findings indicate tactile learning is susceptible to interference from competing tasks within 15-minute window. Our results suggest that tactile memory traces require approximately 60 minutes to achieve stability, providing new insights into the temporal characteristics of somatosensory plasticity and the vulnerability of the consolidation phase.