Developmental changes in point-light walker processing during childhood: a two-year follow-up ERP study

Cortical encoding of rhythmic kinematic structures in biological motion

Biological motion (BM) perception is of great survival value to human beings. The critical characteristics of BM information lie in kinematic cues containing rhythmic structures. However, how rhythmic kinematic structures of BM are dynamically represented in the brain and contribute to visual BM processing remains largely unknown. Here, we probed this issue in three experiments using electroencephalogram (EEG). We found that neural oscillations of observers entrained to the hierarchical kinematic structures of the BM sequences (i.e., step-cycle and gait-cycle for point-light walkers). Notably, only the cortical tracking of the higher-level rhythmic structure (i.e., gait-cycle) exhibited a BM processing specificity, manifested by enhanced neural responses to upright over inverted BM stimuli. This effect could be extended to different motion types and tasks, with its strength positively correlated with the perceptual sensitivity to BM stimuli at the right temporal brain region dedicated to visual BM processing. Modeling results further suggest that the neural encoding of spatiotemporally integrative kinematic cues, in particular the opponent motions of bilateral limbs, drives the selective cortical tracking of BM information. These findings underscore the existence of a cortical mechanism that encodes periodic kinematic features of body movements, which underlies the dynamic construction of visual BM perception.

Three- and six-year-old children are sensitive to natural body expressions of emotion: An event-related potential emotional priming study

Body movements provide a rich source of emotional information during social interactions. Although the ability to perceive biological motion cues related to those movements begins to develop during infancy, processing those cues to identify emotions likely continues to develop into childhood. Previous studies used posed or exaggerated body movements, which might not reflect the kind of body expressions children experience. The current study used an event-related potential (ERP) priming paradigm to investigate the development of emotion recognition from more naturalistic body movements. Point-light displays (PLDs) of male adult bodies expressing happy or angry emotional movements while narrating a story were used as prime stimuli, whereas audio recordings of the words "happy" and "angry" spoken with an emotionally neutral prosody were used as targets. We recorded the ERPs time-locked to the onset of the auditory target from 3- and 6-year-old children, and we compared amplitude and latency of the N300 and N400 responses between the two age groups in the different prime-target conditions. There was an overall effect of prime for the N300 amplitude, with more negative-going responses for happy PLDs compared with angry PLDs. There was also an interaction between prime and target for the N300 latency, suggesting that all children were sensitive to the emotional congruency between body movements and words. For the N400 component, there was only an interaction among age, prime, and target for latency, suggesting an age-dependent modulation of this component when prime and target did not match in emotional information. Overall, our results suggest that the emergence of more complex emotion processing of body expressions occurs around 6 years of age, but it is not fully developed at this point in ontogeny.

Facilitation of biological motion processing by group-based autism specific social skills training

Abnormalities in neurophysiological correlates of social perception are a well-known feature of autism spectrum disorder (ASD). However, little is known if and how ASD specific behavioral interventions may affect neural processing in ASD. The aim of the current study was to investigate for the first time, whether the group-based social skills training SOSTA-FRA would elicit changes in neurophysiological correlates of social perception in high-functioning ASD individuals aged 8-17 years. Event-related potentials (ERPs) of a facial emotion recognition (FER) and a biological motion perception task were examined. ERPs were compared between a randomized intervention and a treatment as usual group at three time points (baseline, post-intervention, and at 3 months follow-up). A reduction of P100 amplitude in the right hemisphere and a trend toward reduced N200 latency in the biological motion task were found after the training only in the intervention group, whereas behavioral performance remained stable. Change in N200 latencies and parent-rated social responsiveness showed small but statistically nonsignificant correlations. No changes were observed regarding FER. Results indicate that the intervention changed neural correlates of social perception in ASD. Especially neural correlates of biological motion perception, which is an important prerequisite for successful social interaction, were sensitive to change. ERPs of social perception tasks that are impaired in ASD can well be used to objectively measure neural processing improvement by behavioral intervention. Autism Res 2018, 11: 1376-1387. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: It is well known that people with autism spectrum disorder (ASD) process social information differently than other people and that these differences can also be seen in their brain activity. We also know that behavioral therapies, such as group-based social skills trainings can help people with ASD improve their behavior. But it is unclear how therapy changes social processing in the brain. The aim of our study was therefore to examine how neural processing of social stimuli changed after behavioral intervention. Comparing a group of children and adolescents that received the group-based social skills training SOSTA-FRA to a control group we found that the neural processing of human motion became faster and involved less brain resources after the intervention, while behavioral performance remained stable. No changes were seen for the processing of emotional facial expressions. We recommend that future studies should also analyze changes in brain function as well as behavioral changes as a secondary therapy outcome parameter.

Neural rhythmic symphony of human walking observation: Upside-down and Uncoordinated condition on cortical theta, alpha, beta and gamma oscillations

Biological motion observation has been recognized to produce dynamic change in sensorimotor activation according to the observed kinematics. Physical plausibility of the spatial-kinematic relationship of human movement may play a major role in the top-down processing of human motion recognition. Here, we investigated the time course of scalp activation during observation of human gait in order to extract and use it on future integrated brain-computer interface using virtual reality (VR). We analyzed event related potentials (ERP), the event related spectral perturbation (ERSP) and the inter-trial coherence (ITC) from high-density EEG recording during video display onset (−200–600 ms) and the steady state visual evoked potentials (SSVEP) inside the video of human walking 3D-animation in three conditions: Normal; Upside-down (inverted images); and Uncoordinated (pseudo-randomly mixed images). We found that early visual evoked response P120 was decreased in Upside-down condition. The N170 and P300b amplitudes were decreased in Uncoordinated condition. In Upside-down and Uncoordinated conditions, we found decreased alpha power and theta phase-locking. As regards gamma oscillation, power was increased during the Upside-down animation and decreased during the Uncoordinated animation. An SSVEP-like response oscillating at about 10 Hz was also described showing that the oscillating pattern is enhanced 300 ms after the heel strike event only in the Normal but not in the Upside-down condition. Our results are consistent with most of previous point-light display studies, further supporting possible use of virtual reality for neurofeedback applications.