Compensatory Hippocampal Recruitment Supports Preserved Episodic Memory in Autism Spectrum Disorder

Jeremy Hogeveen; Marie K Krug; Raphael M Geddert; J Daniel Ragland; Marjorie Solomon

doi:10.1016/j.bpsc.2019.08.009

Compensatory Hippocampal Recruitment Supports Preserved Episodic Memory in Autism Spectrum Disorder

Biol Psychiatry Cogn Neurosci Neuroimaging. 2020 Jan;5(1):97-109. doi: 10.1016/j.bpsc.2019.08.009. Epub 2019 Sep 5.

Authors

Jeremy Hogeveen¹, Marie K Krug², Raphael M Geddert³, J Daniel Ragland⁴, Marjorie Solomon⁵

Affiliations

¹ Department of Psychology, University of New Mexico, Albuquerque, New Mexico; Psychology Clinical Neuroscience Center, University of New Mexico, Albuquerque, New Mexico. Electronic address: [email protected].
² Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, California; MIND Institute, University of California, Davis, Davis, California.
³ Center for Cognitive Neuroscience, Duke University, Durham, North Carolina.
⁴ Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, California; Imaging Research Center, University of California, Davis, Davis, California.
⁵ Department of Psychiatry and Behavioral Sciences, University of California, Davis, Davis, California; MIND Institute, University of California, Davis, Davis, California; Imaging Research Center, University of California, Davis, Davis, California.

Abstract

Background: The degree to which individuals with autism spectrum disorder (ASD) evidence impairments in episodic memory relative to their typically developing (TD) counterparts remains unclear. According to a prominent view, ASD is associated with deficits in encoding associations between items and recollecting precise context details. Here, we evaluated behavioral and neural evidence for this impaired relational binding hypothesis using a task involving relational encoding and recollection during functional magnetic resonance imaging.

Methods: Adolescents and young adults (n_ASD = 47, n_TD = 60) performed the Relational and Item-Specific Encoding task during functional magnetic resonance imaging, including item and associative recognition testing. We modeled functional recruitment within the medial temporal lobes (MTLs), and connectivity between MTL and the posterior medial (PM) network thought to underlie relational memory. The impaired relational binding model would predict a behavioral deficit driven by aberrant recruitment and connectivity of MTL and the PM network.

Results: The ASD and TD groups showed indistinguishable item and associative recognition performance. During relational encoding, the ASD group demonstrated increased hippocampal recruitment, and decreased connectivity between MTL and PM regions relative to the TD group. Within ASD, hippocampal recruitment and MTL-PM connectivity were inversely correlated.

Conclusions: The lack of a behavioral deficit in ASD does not support the impaired relational binding hypothesis. Instead, the current data suggest that increased recruitment of the hippocampus compensates for decreased MTL-PM connectivity to support preserved episodic memory in ASD. These findings suggest a compensatory neurodevelopmental mechanism that may support preserved cognitive domains in ASD: local hyperrecruitment may offset connectivity aberrations in individuals with ASD relative to TD subjects.

Keywords: Autism spectrum disorder; Episodic memory; Functional connectivity; Functional magnetic resonance imaging; Medial temporal lobes; Relational and item-specific memory.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Autism Spectrum Disorder / physiopathology*
Autism Spectrum Disorder / psychology*
Brain Mapping
Child
Female
Hippocampus / physiopathology*
Humans
Magnetic Resonance Imaging
Male
Memory, Episodic*
Mental Recall / physiology
Young Adult

Abstract

Publication types

MeSH terms

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