Role of working memory in interlimb generalization of newly learned skills

Newly acquired skill memory can generalize/transfer to the untrained arm. Such interlimb generalization of a learned skill has been shown to be symmetric in our previous work and can be influenced by cognitive processes that emerge during skill learning. However, it is unknown whether engaging in other cognitively demanding tasks following skill acquisition can influence skill generalization. Our research goal was to uncover how a secondary task, involving working memory, interacts with a newly formed skill memory and influences subsequent interlimb generalization. To test this idea, we conducted a set of three experiments by recruiting right-handed young healthy individuals (N = 92) who learned a novel motor skill (long or short training on a skilled reaching task) followed by performing a working memory or control task with the right arm. Finally, all individuals were tested for immediate or delayed (after 24 h) interlimb skill generalization to the untrained left arm. We found significant immediate as well as delayed generalization in individuals who received long training on the motor skill task, irrespective of whether they performed working memory or control task. On the other hand, performing the working memory but not control task following short skill training impaired generalization when the untrained arm was tested 24 h later. These findings indicate that short training reflecting early stages of skill learning and the subsequent skill memory stabilization are dependent on working memory such that the underlying neural interactions mediating these processes can have implications for skill generalization.