Malinovitch, T. | Search bioRxiv

bioRxiv2020

Impaired online error-correction disrupts synchronization to external events in autism

Autism is a developmental disorder characterized by impaired social skills and accompanied by motor and perceptual atypicalities. Its etiology is an open question, partly due to the diverse range of associated difficulties. Based on recent observations that individuals with autism are slow in updating perceptual priors, we now hypothesized that motor updating is also slow. Slow motor updating is expected to hamper the ability to synchronize to external events, since asynchronies are corrected sluggishly. Since sensorimotor synchronization is important for social bonding and cooperation, its impairment is expected to impair social skills. To test this hypothesis, we measured paced finger tapping to a metronome in neurotypical, ASD, and dyslexia groups. Dyslexia was assessed as a control group with a non-social neurodevelopmental atypicality. Only the ASD group showed reduced sensorimotor synchronization. Trial-by-trial computational modelling revealed that their ability to form controlled motor responses and to maintain reliable temporal representations was adequate. Only their rate of error-correction was slow and was correlated with the severity of their social difficulties. Taken together, these findings suggest that slow updating in autism contributes to both sloppy sensorimotor performance and difficulties in forming social bonds. SignificanceThe prevalence of autism diagnosis has increased immensely is the last decades. Yet its etiology remains a challenge, partly since the functional relations between characteristic social difficulties, perceptual and motor atypicalities are not understood. Using trial-by-trial computational modelling, we show that a single deficit underlies the poor synchronization of individuals with autism in both static and changing environments. Slow updating, leading to slow online error correction of motor plans, has an immense explanatory power explaining both difficulties in sensorimotor synchronization, and social impairments.

neuroscience↗

bioRxiv2020

Training-induced improvement in working memory tasks results from switching to efficient strategies

It is debated whether training with a working memory (WM) task, particularly n-back, can improve general WM and reasoning skills. Most training studies found substantial improvement in the trained task, with little to no transfer to untrained tasks. We hypothesized that training does not increase WM capacity, but instead provides opportunities to develop an efficient task-specific strategy. We derived a strategy for the task that optimizes WM resources and taught it to participants. In two sessions, 14 participants who were taught this strategy performed as well as 14 participants who had trained for forty sessions without strategy instructions. To understand the mechanisms underlying the no-instruction groups improvement, participants answered questionnaires during their training period. Their replies show that successful learners discovered the same strategy and improvement was associated with this discovery. We conclude that n-back training allows the discovery of strategies that enable better performance with the same WM resources.

neuroscience↗