The role of cerebrovascular reactivity on brain activation during a working memory task in type 2 diabetes

INTRODUCTION: Impaired cerebrovascular reactivity (CVR) is common in type 2 diabetes (T2D) patients and is a risk factor for dementia. However, most prior functional magnetic resonance imaging (fMRI) studies in T2D disregarded the impact of impaired CVR on brain activation patterns. This study investigated the relationship between CVR and brain activation during an fMRI task in T2D patients. METHODS: Seventy-four T2D patients underwent a working-memory (WM) fMRI task. CVR was measured by the breath-holding index test using transcranial Doppler (TCD). Regression analyses examined associations between CVR and brain activation and between glycated hemoglobin (HbA1c) and activation with/without adjusting for CVR. RESULTS: An association between CVR and brain activation was found in the left middle and inferior frontal gyri. Adjusting for CVR led to a different pattern of HbA1c-related activation. DISCUSSION: The findings highlight methodological implications, emphasizing the importance of accounting for impaired CVR when analyzing and interpreting fMRI data in T2D patients. Highlights The study found that cerebrovascular reactivity impacts brain activation patterns during a working memory task in type 2 diabetes patients. Accounting for cerebrovascular reactivity altered the brain regions showing activation related to working memory and glycemic control. The findings highlight the importance of considering vascular factors when interpreting fMRI data in populations with vascular dysfunction.