Altered Brain Connectivity in Mild Cognitive Impairment Is Linked to Elevated Tau and Phosphorylated Tau, But Not to Gap-43 and Amyloid-Β Measurements: A Resting-State Fmri Study Publisher Pubmed



Sadeghi M¹ ; Azargoonjahromi A² ; Nasiri H³ ; Yaghoobi A⁴ ; Sadeghi M¹ ; Chavoshi SS⁶ ; Baghaeikia S⁷ ; Mahzari N⁸ ; Valipour A⁹ ; Razeghi Oskouei R¹⁰ ; Shahkarami F¹¹ ; Amiri F¹² ; Mayeli M⁴
Source: Molecular Brain Published:2024

Abstract

Mild Cognitive Impairment (MCI) is a neurological condition characterized by a noticeable decline in cognitive abilities that falls between normal aging and dementia. Along with some biomarkers like GAP-43, Aβ, tau, and P-tau, brain activity and connectivity are ascribed to MCI; however, the link between brain connectivity changes and such biomarkers in MCI is still being investigated. This study explores the relationship between biomarkers like GAP-43, Aβ, tau, and P-tau, and brain connectivity. We enrolled 25 Participants with normal cognitive function and 23 patients with MCI. Levels of GAP-43, Aβ1–42, t-tau, and p-tau181p in the CSF were measured, and functional connectivity measures including ROI-to-voxel (RV) correlations and the DMN RV-ratio were extracted from the resting-state fMRI data. P-values below 0.05 were considered significant. The results showed that in CN individuals, higher connectivity within the both anterior default mode network (aDMN) and posterior DMN (pDMN) was associated with higher levels of the biomarker GAP-43. In contrast, MCI individuals showed significant negative correlations between DMN connectivity and levels of tau and P-tau. Notably, no significant correlations were found between Aβ levels and connectivity measures in either group. These findings suggest that elevated levels of GAP-43 indicate increased functional connectivity in aDMN and pDMN. Conversely, elevated levels of tau and p-tau can disrupt connectivity through various mechanisms. Thus, the accumulation of tau and p-tau can lead to impaired neuronal connectivity, contributing to cognitive decline. © The Author(s) 2024.