Social Memory Deficits In Individuals With Autism Spectrum Disorders Associated With The Hippocampal CA2 Region

Autism spectrum disorder(ASD)is a heterogeneous neurodevelopmental disorder characterized by repetitive stereotypical behavior,social deficits,narrow interests,and language communication disorders.ASD patients with social impairments often experience difficulties in interpersonal communication and social adaptation,which bring great inconvenience and psychological pressure to the lives of ASD patients and caregivers.Social memory is the ability to identify unfamiliar and familiar individuals of the same kind and retrieve social related information from past experiences.It is the prerequisite and foundation for individuals to engage in social interaction,cooperation,and communication.Social memory helps individuals establish and develop social relationships,maintain social and emotional connections with others,and is a necessary condition for normal social interaction.It is crucial for human survival and reproduction.Social memory impairment is one of the important reasons for social impairment in ASD.Patients with ASD often exhibit resistance to social interaction and difficulty identifying new and old faces.Previous studies have shown that the hippocampal CA2 region plays a central role in social memory function,but it is unclear how the hippocampal CA2 region regulates social memory function in patients with ASD.Therefore,in order to explore the role of the hippocampal CA2 region in social memory function in individuals with ASD,this study was the first time in China to use an ASD animal model,BTBR mice,and wild-type C57 mice as controls.After testing typical autistic behavior,in vivo multi-channel recording technology was used to record the neural electrical activity of the hippocampal CA2 region in mice during free activity,Further,different social scenarios were created to synchronously record and analyze the social behavior of mice and the neurophysiological changes in the CA2 region of the hippocampus.Finally,immunochemical staining techniques were used to compare the morphological characteristics of the CA2 region of the mouse hippocampus.This study draws the following conclusions:(1)Compared with C57 mice,BTBR mice exhibit severe social deficits and repetitive stereotypical behaviors,exhibiting typical autistic behavior.(2)Compared with C57 mice,the social memory function of BTBR mice was significantly impaired.(3)Compared with C57 mice,BTBR mice exhibit atypical neuronal oscillatory activity in the CA2 region of the hippocampus related to social memory.During social interaction,the hippocampal CA2 region of BTBR mice is low γ Significant reduction in power,low γ Synchronization may be one of the characteristics of social memory deficits in ASD.(4)The number of cells in the CA2 region of the hippocampus of BTBR mice was significantly lower than that of C57 mice,with significant differences in morphology.Impairment or developmental abnormalities in the CA2 region of the hippocampus may be the cause of social memory deficits in individuals with ASD.Through in-depth and systematic exploration of the social memory function of individuals with ASD related to the CA2 region of the hippocampus,this study has deepened the understanding of the pathology of ASD,and is conducive to targeted intervention and targeted drug therapy for social related disorders of ASD.