A HierarchicalModel for AutismSpectrumDisorder (HMASD)


1 Paediatric Neurology Division, QaemHospital,Mashhad University of Medical Sciences,Mashhad, IR Iran

2 Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, IR Iran

3 Department of Biomedical Engineering, Amir Kabir University of Technology, Tehran, IR Iran

4 Department of Paediatrics, Dr Sheikh Paediatric Hospital,Mashhad University of Medical Sciences, IR Iran



Abstract Background: Autismspectrumdisorder (ASD) is a severe behavioral disorder characterized by pervasive impairments in social in- teractions, deficits in verbal and nonverbal communication, and stereotyped, repetitive patterns of behaviors and interests. Despite recent advances in identifying some genes that may cause autism, its underlying neurological mechanisms are uncertain. ASD is best conceptualized by considering the neural systems thatmay be defective in autistic individuals. Objectives: Here,we aimto describe a potentialHierarchicalmodel for ASD. This interesting presentedmodel is based on excitatory and inhibitory characteristics of cortico-cortical networks. Methods: Jasonmodel is one of themodels applied to produce EEG in cortical areas. In thismodel, a cortical area ismodeled with three subpopulations including: excitatory pyramidal cells (output), excitatory interneurons groups, input inhibitory interneuron groups bymeans of output connections (output connections are limited to cortical planes). The presented hierarchicalmodel for autism spectrum disorder (HMASD) is based on Jason model. HMASD is a hierarchical model of cortico-cortical networks as well as an excitation/inhibition model in sensory, mnemonic, social and emotional systems. In HMASD there are three kinds of outer connections including forward, backward and lateral connections, that their power is controlled by coupling parameters. Results: HMASD raises the possibility that ASD is related to excitation/inhibition imbalance in cortico-cortical networks. HMASD parameters are possible way for quantization imbalance quality. Conclusions: Themost effected parts in ASD are lateral connections of HMASD. Two-sided connections which are completely sym- metric become more active, and cause extra synchronization. On the other hand, due to special characteristic of two-sided con- nections and their ability to simulate the same phased dynamics, they cause unnatural asymmetry in children’s EEG signal. These results are consistent with previous findings suggesting the association of EEG abnormalities in ASD with functional impairment of information interacted in cortical connections.