Where and how does our brain represent action sequences?

A new study by the Gazzola and Keysers groups show that the brain encodes sequence-related information in the motor system. This sheds light on how we adapt to the actions of others and suggests that the motor system may implement perceptual predictive coding. The study is published in NeuroImage.

It has long been recognized that when we see individual actions (like grasping), we recruit motor regions involved in performing the action, and this makes our perception more accurate. There has been debate however, about whether the way that these actions are chained together to achieve larger goals (e.g. preparing dinner) would also be processed in the motor system, or whether cognitive prefrontal regions are processing these longer temporal scales. In this study, using a combination of fMRI and EEG and using innovative analysis techniques, the scientists show that motor regions do represent these higher order chains. They also show that imbedding actions in sequences reduces the visual response to the elements and increases the motor representations, suggesting that a predictive coding scheme seems to be at work during action observation.