Hippocampal contributions to social and cognitive deficits in autism spectrum disorder

Abstract

Autism spectrum disorder (ASD) is characterized by hallmark impairments in social functioning. Nevertheless, nonsocial cognition, including hippocampus-dependent spatial reasoning and episodic memory, is also commonly impaired in ASD. ASD symptoms typically emerge between 12 and 24 months of age, a time window associated with critical developmental events in the hippocampus. Despite this temporal overlap and evidence of hippocampal structural abnormalities in ASD individuals, relatively few human studies have focused on hippocampal function in ASD. Herein, we review the existing evidence for the involvement of the hippocampus in ASD and highlight the hippocampus as a promising area of interest for future research in ASD.

Keywords: cognitive mapping; fMRI; memory; neurodevelopmental disorders; social; spatial.

Figure 1 (Key Figure).

Hippocampal abnormalities may contribute to aspects of the ASD phenotype. Structural and functional alterations of the hippocampus may lead to disruptions in the abilities it subserves, including memory, spatial reasoning, and social interaction. Subsequent deficits in these functions may contribute to an ASD phenotype. Figure created with BioRender.com.

Figure 2:

Impairments in reciprocal social relationships, spatial reasoning, and memory are components of the three main symptom clusters that comprise the ASD phenotype. The hippocampus is known to support these behaviors; hippocampal abnormalities may thus lead to some of the symptoms commonly observed in ASD. Though there is a lack of direct evidence for hippocampal involvement in insistence on sameness, a prevalent symptom in ASD characterized by ritualistic behaviors and circumscribed interests, altered functioning of the hippocampus may lead to such behaviors through impairments in cognitive mapping. The size of the circles represents the prominence of each symptom in the ASD phenotype, with larger circles indicating aspects that are more at the core of the disorder. Figure created with BioRender.com.

Figure 3.

Cognitive mapping across domains. Cognitive maps store representations of the relationships between elements, including A) memories, B) physical locations, and C) social relationships. In some experimental paradigms, social relationships are conceptualized within a two-dimensional map, as illustrated in the schematic, of varying degrees of affiliation and power. Figure created with BioRender.com.