rTMS modulates precuneus-hippocampal subregion circuit in patients with subjective cognitive decline

Abstract

Hippocampal subregions (HIPsub) and their network connectivities are generally aberrant in patients with subjective cognitive decline (SCD). This study aimed to investigate whether repetitive transcranial magnetic stimulation (rTMS) could ameliorate HIPsub network connectivity by modulating one node of HIPsub network in SCD. In the first cohort, the functional connectivity (FC) of three HIPsub (i.e., hippocampal emotional, cognitive, and perceptual regions: HIPe, HIPc, and HIPp) were analyzed so as to identify alterations in HIPsub connectivity associated with SCD. Afterwards, a support vector machine (SVM) approach was applied using the alterations in order to evaluate to what extent we could distinguish SCD from healthy controls (CN). In the second cohort, a 2-week rTMS course of 5-day, once-daily, was used to activate the altered HIPsub network connectivity in a sham-controlled design. SCD subjects exhibited distinct patterns alterations of HIPsub network connectivity compared to CN in the first cohort. SVM classifier indicated that the abnormalities had a high power to discriminate SCD from CN, with 92.9% area under the receiver operating characteristic curve (AUC), 86.0% accuracy, 83.8% sensitivity and 89.1% specificity. In the second cohort, changes of HIPc connectivity with the left parahippocampal gyrus and HIPp connectivity with the left middle temporal gyrus demonstrated an amelioration of episodic memory in SCD after rTMS. In addition, SCD exhibited improved episodic memory after the rTMS course. rTMS therapy could improve the posterior hippocampus connectivity by modulating the precuneus in SCD. Simultaneous correction of the breakdown in HIPc and HIPp could ameliorate episodic memory in SCD. Thus, these findings suggested that rTMS manipulation of precuneus-hippocampal circuit might prevent disease progression by improving memory as the earliest at-risk state of Alzheimer’s disease in clinical trials and in practice.

Disrupted Dynamic Functional Connectivity in Distinguishing Subjective Cognitive Decline and Amnestic Mild Cognitive Impairment Based on the Triple-Network Model

“…Functional MRI images were analyzed as described in previous studies using the DPABI based on the SPM program, implemented in MATLAB2013b with the following steps (Chen et al, 2016a(Chen et al, , 2020: We discarded the first 10 volumes and performed slice-timing correction and head motion correction. The participants with excessive head motion (cumulative translation or rotation of > 3. mm or 3.…”

Functional Integrity of Executive Control Network Contributed to Retained Executive Abilities in Mild Cognitive Impairment

“…Finally, we carried out filtering band-pass (0.01-0.08 Hz) (Chen et al, 2016) prior to calculating seed-based functional connectivity (FC), and after calculating fALFF. In addition, participants with excessive head motion (cumulative translation or rotation >3.0 mm or 3.0) were excluded (Chen et al, 2020;Wang et al, 2021a).…”

Differential Abnormality in Functional Connectivity Density in Preclinical and Early-Stage Alzheimer's Disease

“…The data for the applied research were obtained from our domestic database, the Nanjing Brain Hospital Alzheimer's Disease Spectrum Neuroimaging Project (NBH-ADsnp) (Nanjing, China; Chen et al, 2020 ; Wang et al, 2021 ; Xu et al, 2021 ), which is regularly updated. Detailed information about NBH-ADsnp is available in the Supplementary Material .…”