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 people's actions, a largely unanswered question in neuroscience is how experience shapes the representational space of neural systems. Here, across a sample of male and female participants, 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 human 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 to that previously shown following 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