Lateralized Contributions of Medial Prefrontal Cortex Network to Episodic Memory Deficits in Subjects With Amnestic Mild Cognitive Impairment

Abstract

Both episodic memory and executive function are impaired in amnestic mild cognitive impairment (aMCI) subjects, but it is unclear if these impairments are independent or interactive. The present study aimed to explore the relationship between episodic memory deficits and executive function deficits, and the underlying functional mechanisms in aMCI subjects. Thirty-one aMCI subjects and 27 healthy subjects underwent neuropsychological tests and multimodal magnetic resonance imaging (MRI) scans. Hippocampal networks and medial prefrontal cortex (MPFC) networks were identified based on resting-sate functional MRI (fMRI) data. AMCI subjects displayed lower episodic memory scores and executive function scores than control subjects, and the episodic memory scores were positively correlated with the executive function scores in aMCI subjects. Brain network analyses showed an interaction between the hippocampal networks and the MPFC networks, and the interaction was significantly associated with the episodic memory scores and the executive function scores. Notably, aMCI subjects displayed higher functional connectivity (FC) of the right hippocampal network with the right prefrontal cortex than did control subjects, but this difference disappeared when controlling for the MPFC networks. Furthermore, the effects of the MPFC networks on the hippocampal networks were significantly associated with the episodic memory scores in aMCI subjects. The present findings suggested that the episodic memory deficits in aMCI subjects could be partially underpinned by the modulation of the MPFC networks on the hippocampal networks.

Functional changes of the prefrontal cortex, insula, caudate and associated cognitive impairment (chemobrain) in NSCLC patients receiving different chemotherapy regimen

“…The medial prefrontal cortex (mPFC) has abundant connections with other cortical and subcortical regions, which makes it as an essential cortical region for integrating information from other areas and converging updated information to other areas in the brain ( 35 ). Take into consideration of its crucial role in the cognitive process including attention, working memory, spatial learning and emotional response, dysfunction of mPFC has been found in various psychiatric and neurological disorders with cognitive impairment ( 36 , 37 ). Post-chemotherapy lung cancer patients exhibited decreased FC in the left mPFC when compared with non-chemotherapy lung cancer patients ( 22 ).…”

Episodic memory network characteristics in patients with amnestic mild cognitive impairment accompanied by executive function impairment

“…Multiple studies have previously found varying degrees of EMN impairment in the AD spectrum, which lead to cognitive decline (Cai et al, 2017;Cassady et al, 2021;Liang et al, 2022). Moreover, Ye et al (2021) found a correlation between EF and EMN (F. Bai et al, 2016). However, whether EF influences EMN, thereby mediating EM function, remains to be investigated.…”

“…Yuan et al (2016) highlighted EF as a key predictor for aMCI to AD conversion, with impaired EF exacerbating EM defects and increasing the risk of progression to AD. Ye et al (2021) suggested that the EM defects in aMCI may be partially due to impaired EF. However, the mechanism by which EF in aMCI patients affects EM…”

“…Ye et al. ( 2021 ) suggested that the EM defects in aMCI may be partially due to impaired EF. However, the mechanism by which EF in aMCI patients affects EM is not yet clear.…”

“…Moreover, Ye et al. ( 2021 ) found a correlation between EF and EMN (F. Bai et al., 2016 ). However, whether EF influences EMN, thereby mediating EM function, remains to be investigated.…”