Lay Abstract Individuals with autism spectrum disorder (ASD) show deficits in acquiring a wide range of skills including social communication skills, a defining feature of ASD, as well as basic motor skills. Development of even the most basic skill involves integrating information from multiple senses. Learning skilled social gestures is particularly reliant on integration of visual and tactile information. To better understand this process, we used a serial response time task to explore how adults with ASD use visual and proprioceptive input to promote motor learning as compared to healthy controls. In line with prior studies of motor adaptation, we find that individuals with ASD show an anomalous pattern of learning. While both groups learned the implicit motor sequence during training there was decreased reliance on visual input during generalization, as compared to healthy controls. The findings have important implications for understanding the brain basis of impaired skill learning and for understanding approaches for improving these skills in individuals with ASD. Effective learning strategies may leverage guided performance and proprioceptive input or facilitate development of visual-motor connections. Scientific Abstract In addition to defining impairments in social communication skills, individuals with autism spectrum disorder (ASD) also show impairments in more basic sensory and motor skills. Development of new skills involves integrating information from multiple sensory modalities. This input is then used to form internal models of action that can be accessed when both performing skilled movements, as well as understanding those actions performed by others. Learning skilled gestures is particularly reliant on integration of visual and proprioceptive input. We used a modified serial reaction time task (SRTT) to decompose proprioceptive and visual components and examine whether patterns of implicit motor skill learning differ in ASD participants as compared to healthy controls. While both groups learned the implicit motor sequence during training, healthy controls showed robust generalization whereas ASD participants demonstrated little generalization when visual input was constant. In contrast, no group differences in generalization were observed when proprioceptive input was constant, with both groups showing limited degrees of generalization. The findings suggest, when learning a motor sequence, individuals with ASD tend to rely less on visual feedback than do healthy controls. Visuomotor representations are considered to underlie imitative learning and action understanding and are thereby crucial to social skill and cognitive development. Thus, anomalous patterns of implicit motor learning, with a tendency to discount visual feedback, may be an important contributor in core social communication deficits that characterize ASD.

Motor impairments are prevalent in children with autism spectrum disorder (ASD). The Serial Reaction Time Task (SRTT), a well-established visuomotor sequence learning probe, has produced inconsistent behavioral findings in ASD. Moreover, it remains unclear how neural processes underlying SRTT learning in autism compare to processes for TD children. Neural activity differences were assessed using fMRI during a visuomotor sequence learning task in children with and without autism. Though there was no group difference on SRTT performance, underlying patterns of neural activation significantly differed when comparing sequence (i.e. learning) to random (i.e. non-learning) blocks. Children with autism demonstrated decreased activity in brain regions implicated in visuomotor sequence learning: superior temporal sulcus, and posterior cingulate cortex. The findings implicate autism-associated differences in brain mechanisms necessary to initial sequence learning and may help to explain behavioral observations of autism-associated impairments in skill development (motor, social, communicative) reliant on visuomotor integration.

Mirroring neurons fire both when an individual moves and observes another move in kind. This simulation of others' movements is thought to effortlessly and ubiquitously support empathetic connection and social understanding. However, at times this could be maladaptive. How could a boxer mirror a losing opponent's expressions of fatigue, feeling his weariness, precisely when strength is required? Clearly, the boxer must emotionally disconnect from his opponent and those expressions of fatigue must become irrelevant and not mirrored. But, movements that inform of his opponent's intentions to deliver an incoming blow are quite relevant and still should require mirroring. We tested these dimensions of emotional connectedness and relevance of movement in an electroencephalography experiment, where participants' desires to socially connect with a confederate were manipulated. Before manipulation, all participants mirrored the confederate's purely kinematic (a hand opening and closing) and goal-directed (a hand opening and closing around a token that the participant desired) hand movements. After manipulation, unfairly treated subjects ceased to mirror the purely kinematic movements but continued to mirror goal-relevant movements. Those treated fairly continued to mirror all movements. The results suggest that social mirroring can be adaptive in order to meet the demands of a varied social environment.