Walk like me, talk like me. The connection between mirror neurons and autism spectrum disorder

Segregated Dynamical Networks for Biological Motion Perception in the Mu and Beta Range Underlie Social Deficits in Autism

OBJECTIVE

Biological motion perception (BMP) correlating with a mirror neuron system (MNS) is attenuated in underage individuals with autism spectrum disorder (ASD). While BMP in typically-developing controls (TDCs) encompasses interconnected MNS structures, ASD data hint at segregated form and motion processing. This coincides with less fewer long-range connections in ASD than TDC. Using BMP and electroencephalography (EEG) in ASD, we characterized directionality and coherence (mu and beta frequencies). Deficient BMP may stem from desynchronization thereof in MNS and may predict social-communicative deficits in ASD. Clinical considerations thus profit from brain-behavior associations.

METHODS

Point-like walkers elicited BMP using 15 white dots (walker vs. scramble in 21 ASD (mean: 11.3 ± 2.3 years) vs. 23 TDC (mean: 11.9 ± 2.5 years). Dynamic Imaging of Coherent Sources (DICS) characterized the underlying EEG time-frequency causality through time-resolved Partial Directed Coherence (tPDC). Support Vector Machine (SVM) classification validated the group effects (ASD vs. TDC).

RESULTS

TDC showed MNS sources and long-distance paths (both feedback and bidirectional); ASD demonstrated distinct from and motion sources, predominantly local feedforward connectivity, and weaker coherence. Brain-behavior correlations point towards dysfunctional networks. SVM successfully classified ASD regarding EEG and performance.

CONCLUSION

ASD participants showed segregated local networks for BMP potentially underlying thwarted complex social interactions. Alternative explanations include selective attention and global-local processing deficits.

SIGNIFICANCE

This is the first study applying source-based connectivity to reveal segregated BMP networks in ASD regarding structure, cognition, frequencies, and temporal dynamics that may explain socio-communicative aberrancies.

Computational model of decreased suppression of mu rhythms in patients with Autism Spectrum Disorders during movement observation—preliminary findings

Objectives

Autism Spectrum Disorders (ASD) represent developmental conditions with deficits in the cognitive, motor, communication and social domains. It is thought that imitative behaviour may be impaired in children with ASD. The Mirror Neural System (MNS) concept plays an important role in theories explaining the link between action perception, imitation and social decision-making in ASD.

Methods

In this study, Emergent 7.0.1 software was used to build a computational model of the phenomenon of MNS influence on motion imitation. Seven point populations of Hodgkin–Huxley artificial neurons were used to create a simplified model.

Results

The model shows pathologically altered processing in the neural network, which may reflect processes observed in ASD due to reduced stimulus attenuation. The model is considered preliminary—further research should test for a minimally significant difference between the states: normal processing and pathological processing.

Conclusions

The study shows that even a simple computational model can provide insight into the mechanisms underlying the phenomena observed in experimental studies, including in children with ASD.

EEG sensorimotor rhythms in children with autism spectrum disorders

One of the currently assumed causes of impaired social interaction exhibited by children with autism spectrum disorders (ASD) is dysfunction of the mirror neuron system (MNS), which is responsible for imitation, understanding the intentions and emotions of other people. Desynchronization of sensorimotor rhythms is considered to be the indicator of MNS activation. This study aimed to analyze the specific patterns of reactivity of the μ-rhythm in an individually determined frequency range and β-rhythm on the EEG in children with ASD during independent movements, observation, imitation and auditory perception of similar movements performed by another person. The data collected were compared to those describing normally developing children. The study involved right-handed children with ASD aged 5–10 (n = 10) and normally developing children (n = 10). In the independent movements exercise, β-rhythm desynchronization was more pronounced in children with ASD, with difference becoming significant in the P4 locus (p = 0.03). In the movements imitation exercise, the groups showed significant differences in the EEG μ-rhythm in the locus C3 (p = 0.03). Auditory perception of movements revealed significant differences in the ranges of both μ-rhythm (loci F3 and Fz (p = 0.02), F4 (p = 0.04), Cz (p = 0.009)) and β-rhythm (loci Fz (p = 0.01), F4 (p = 0.02)). In these situations, children with ASD exhibited synchronization of sensorimotor rhythms, while normally developing children showed desynchronization. The assumption is that the specific patterns revealed are the consequences of disruption of functions of MNS and anti-mirror system. The data obtained can be used in development of EEG biofeedback training protocols for children with ASD.

High-Frequency Repetitive Transcranial Magnetic Stimulation Applied to the Parietal Cortex for Low-Functioning Children With Autism Spectrum Disorder: A Case Series

Background: Repetitive transcranial magnetic stimulation (rTMS) is a safe and efficacious technique to stimulate specific areas of cortical dysfunction in several neuropsychiatric diseases; however, it is not known whether high-frequency rTMS (HF-rTMS) over the left inferior parietal lobule, in low functioning children with autism spectrum disorder (ASD), improves core symptoms. Method: Eleven low-functioning children with ASD completed two separate HF-rTMS treatment courses, 6 weeks apart. Each treatment course involved five 5-s trains at 20 Hz, with 10-min inter-train intervals, on left inferior parietal lobule each consecutive weekday for a 3-week period (15 treatments per course). Subjects were assessed at five time points: immediately before and after the first HF-rTMS course, immediately before and after the second HF-rTMS course, and 6 weeks after the second rTMS treatment course. Treatment effectiveness was evaluated using the Verbal Behavior Assessment Scale (VerBAS) and Autism Treatment Evaluation Checklist (ATEC). The latter test consists of four subtest scales: Language, Sociability, Sensory, and Behavior. In addition, daily treatment logbooks completed by parents were considered as one of the outcome measures. Results: Participants showed a significant reduction in language- and social-related symptoms measured by ATEC from pretreatment to the 6-week follow-up after the second treatment course. Moreover, some possible improvements in imitation and cognition were reported by caregivers. Conclusions: Our findings suggest that HF-rTMS over the left parietal cortex might improve core deficits in low-functioning children with ASD.

Motor competency and social communication skills in preschool children with autism spectrum disorder

This study aimed to investigate the association between motor competency and social communication in children with Autism Spectrum Disorder (ASD) compared with children with Intellectual Disabilities (ID) and typically developing (TD) children. Motor competency, ASD symptoms, and nonverbal Intelligent Quotient (IQ) were investigated through the following tests: Movement Assessment Battery for Children, second edition (MABC-2), Social Communication Questionnaire (SCQ), Autism Classification System of Functioning: Social Communication (ACSF:SC) and Leiter International Performances Scale Revised (Leiter-R). The ASD + ID and ID groups had lower MABC-2-manual dexterity mean scores, MABC-2-aiming and catching mean scores, MABC-2-static and dynamic balance mean scores and MABC-2-TTS compared with the TD group (P < 0.05). In addition, the ASD + ID group had lower MABC-2-aiming and catching mean scores compared with the ID group. In the ASD + ID group, we found a significant negative correlation (P < 0.001) between MABC-2-aiming and catching scores with SCQ scores, nonverbal IQ and ACSF:SC levels. Our findings provide new insight into the common neuropsychological mechanisms underlying social communication and motor deficits in ASD. Multiple deficits in motor functioning may be present in ASD and ID, however deficits involving the ability to integrate motor and social cues are somewhat specific to ASD. Autism Res 2018, 11: 893-902. © 2018 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

This study highlighted the specificity of motor impairment in ASD comparing performances on a frequently used measure of motor impairment between clinical groups (ASD + ID and ID) and a non-clinical group. While previous research has suggested that multiple deficits in motor functioning may be present in ASD, our findings suggest that deficits in tasks involving the ability to integrate visual and motor cues (aiming and catching task) are somewhat specific to ASD.

Frontal lobe alterations in schizophrenia: a review

Abstract Objective: To highlight the changes in the frontal lobe of the human brain in people with schizophrenia. Methods: This was a qualitative review of the literature. Results: Many schizophrenic patients exhibit functional, structural, and metabolic abnormalities in the frontal lobe. Some patients have few or no alterations, while some have more functional and structural changes than others. Magnetic resonance imaging (MRI) shows structural and functional changes in volume, gray matter, white matter, and functional activity in the frontal lobe, but the mechanisms underlying these changes are not yet fully understood. Conclusion: When schizophrenia is studied as an essential topic in the field of neuropsychiatry, neuroscientists find that the frontal lobe is the most commonly involved area of the human brain. A clear picture of how this lobe is affected in schizophrenia is still lacking. We therefore recommend that further research be conducted to improve understanding of the pathophysiology of this psychiatric dilemma.