Characterizing the relationship between episodic memory and hippocampal functional networks in individuals at familial risk for schizophrenia

Poster Session C - Sunday, March 30, 2025, 5:00 – 7:00 pm EDT, Back Bay Ballroom/Republic Ballroom

Aslihan Imamoglu¹, Mackenzie E. Mitchell², Tehila Nugiel³, Mackenzie Woodburn⁴, Jessica R. Cohen⁵, Aysenil Belger⁵, Kelly S. Giovanello⁵; ¹Vanderbilt University Medical Center, ²University of Illinois, Urbana-Champaign, ³Florida State University, ⁴Nature Communications, ⁵University of North Carolina, Chapel Hill

Episodic memory impairments are consistently observed in individuals with first-episode psychosis and chronic schizophrenia, as well as their high-risk, first-degree relatives. In individuals with schizophrenia, these impairments have been linked to disruptions in the modularity of two hippocampal resting-state networks integral to episodic memory: the hippocampal-medial temporal lobe cortex (MTLC) and the extended hippocampal cortical networks. The current study extends these findings by characterizing the relationship between resting-state hippocampal modularity and episodic memory in individuals at high familial risk for schizophrenia. Participants were 73 children and adolescents (aged 9 to 16 years old) who completed a measure of episodic memory (i.e., delayed-free recall task), as well as a 6-minute resting-state scan. We hypothesized that when compared to age-matched healthy controls (N = 49), participants at high familial risk for schizophrenia (N = 24) would exhibit reduced modularity in the core hippocampal-MTLC network, and that this difference in modularity would relate to lower accuracy on the free recall task. We also hypothesized that both groups would show comparable modularity in the extended hippocampal-cortical network, consistent with findings in schizophrenia. Contrary to our hypothesis, the two groups were comparable in the modularity of both hippocampal networks. Notably, modularity for these two networks was unrelated to episodic memory performance. These findings suggest that the modularity of functional hippocampal networks may not serve as an endophenotype in individuals at familial risk for schizophrenia but instead may be associated with the onset or progression of the disease state.

Topic Area: LONG-TERM MEMORY: Episodic