Observing action sequences elicits sequence-specific neural representations in frontoparietal brain regions
Learning new skills by watching others is important for social and motor development throughout the lifespan. Prior research has suggested that observational learning shares common substrates with physical practice at both cognitive and brain levels. In addition, neuroimaging studies have used multivariate analysis techniques to understand neural representations in a variety of domains including vision, audition, memory and action, but few studies have investigated neural plasticity in representational space. As such, although movement sequences can be learned by observing other peoples actions, a largely unanswered question in neuroscience is how experience shapes the representational space of neural systems. Here we combined pre- and post-training fMRI sessions with six days of observational practice to examine whether the observation of action sequences elicits sequence-specific representations in frontoparietal brain regions and the extent to which these representations become more pronounced with observational practice. Our results showed that observed action sequences are modelled by distinct patterns of activity in frontoparietal cortex and that such representations largely generalise to very similar, but untrained, sequences. These findings advance our understanding of what is modelled during observational learning (sequence-specific information), as well as how it is modelled (reorganisation of frontoparietal cortex is similar manner to that of physical practice). Thus, on a more fine-grained neural level than demonstrated previously, we show the representational structure of how frontoparietal cortex maps visual information onto motor circuits to order to enhance motor performance.\n\nSignificance statementLearning by watching others is a cornerstone in the development of expertise and skilled behaviour. However, it remains unclear how visual signals are mapped onto motor circuits for such learning to occur. Here we show that observed action sequences are modelled by distinct patterns of activity in frontoparietal cortex and that such representations largely generalise to very similar, but untrained, sequences. These findings advance our understanding of what is modelled during observational learning (sequence-specific information), as well as how it is modelled (reorganisation of frontoparietal cortex is similar manner to that of physical practice). More generally, these findings demonstrate how motor circuit involvement in the perception of action sequences shows high fidelity to the physical performance of action sequences.