Identifying Behavioural and Neural Indices of Sensorimotor Experience Among Young Adults and Adolescents

The ability to encode kinematic information related to observed actions is often an important aspect of sporting as well as artistic performance. However, differences in performers’ action experience could potentially guide how these individuals are able to perceive actions. Moreover, the ability to encode sensorimotor differences in the way actions have been experienced may be particularly relevant for complex motor learning involving the acquisition of intransitive actions. To investigate this possibility, a behavioural study was conducted to examine whether individuals can explicitly identify their own action experiences with whole-body actions following a period of differentiated sensorimotor training. Participants were simply asked to identify whether specific actions had been physically experienced, observed, or untrained during a week of prior training. The ability to predict an individual’s overall performance fidelity for these movements using scores on the categorisation task suggests the ability to distinguish sensorimotor information related to action experience may be associated with an individual’s ability to benefit from a motor training paradigm. In addition, we wished to examine whether specific neural indices could be used to distinguish between perceived actions based on the prior experience of an observer. Recent 14 findings from neuroimaging suggest that the ability to perceive observed actions is related to the functioning of a network of regions known as the Action Observation Network. However, both increased as well as reduced levels of action experience have been associated with increased activity within these regions. The apparent conflict within this literature may be driven by the differences in methodology used to assess engagement within this network. Namely, action features such as intent, overall expertise, and visual identity, may be some of the factors that influence this engagement alongside individual experience. As such, a primary goal of this work was to investigate whether these regions encode differences in experience when observing actions in a format that emphasises differences in kinematics above other features. Overall, patterns of voxel activity within the adult AON did appear to discriminate between different forms of experience in the relative absence of magnitude based differences due to experience. These patterns may reflect how frequently observed actions are encoded primarily using visuospatial information within regions of the brain responsible for processing visual information related to moving bodies, while actions that have also been physically experienced may benefit from sensorimotor feedback leading to visuomotor integration. Although the interaction between motor learning and action perception has been addressed during infancy, the impact of experience on action perception has received limited attention during other periods of rapid developmental change, which may have variable implications for motor learning during these periods. Given that various hormonal, behavioural, and neural changes accompany adolescence, the ability to anticipate the actions of others may be influenced in a different form as higher-level sensorimotor cortices continue to mature into adulthood. In this case, we did not find that sensorimotor experience was related to the magnitude of AON engagement among adolescents, nor did we find strong 15 evidence for patterns of AON voxel activity that could differentiate between different types of sensorimotor experience. However, voxel activity in the caudate nucleus that could be used to discriminate between physically trained and observed actions within this group suggest that activity within this region could influence action perception during this period. In addition, heightened discriminability of sensorimotor experience based on voxel patterns within higher-level sensorimotor cortices was found among adults compared to adolescents. This finding suggests that increased maturity within higher-level sensorimotor cortices could influence how action perception is affected by experience and that adolescents may rely on lower-level visuospatial encoding of movements to perceive actions. Overall, these studies shed new light on how action perception is shaped through experience while informing theories of action perception in contexts involving complex and intransitive actions. Further work in this field should ultimately seek to address how specific indices of sensorimotor experience may be related to motor learning potential, as well as examining whether these indices are domain-general or specific to an individual’s own action expertise. Gaining deeper insight to perceiving the actions of others could ultimately benefit training paradigms across a variety of educational and rehabilitative contexts