Objective: For proper cognitive function, the integrity of resting-state functional brain networks (RSNs) is crucial. Cognitive decline is common in type 1 diabetes mellitus (T1DM), possibly as a result of changes in RSNs, which may vary depending on microvascular complication status. Using an impartial method and a high spatio-temporal resolution functional network, we therefore tested the hypothesis that functional connectivity in RSNs differs according to clinical status and correlates with cognition in T1DM patients.
Methods: We collected resting-state magnetoencephalographic (MEG) data from 33 healthy participants and 42 T1DM patients with and without microvascular complications. A new atlas-based beamformer was used to reconstruct MEG time series at the source level. The phase lag index (PLI) was used to estimate functional connectivity within classical frequency bands within eight commonly observed RSNs. Cognitive performance was evaluated using neuropsychological tests, and the connection to RSNs was examined.
Results: The default-mode (DMN), executive control (ECN), and sensorimotor (SMN) RSN functional connectivity between the three groups was significantly different in the lower alpha band. In comparison to the other groups, T1DM patients with microvascular complications had the lowest functional connectivity in these networks. Functional connectivity for DMN was greater in patients who did not have microangiopathy than in controls (all p 0.05). When compared to healthy controls, the general cognitive performance of both patient groups was lower. In patients with microvascular complications, lower DMN alpha band functional connectivity was associated with lower general cognitive ability.
Discussion: Depending on their clinical status, T1DM patients had altered RSN functional connectivity. Cognitive impairment was linked to lower DMN functional connectivity. Based on these findings, functional connectivity may play a significant role in cognitive dysfunction caused by T1DM.
