Altered functional connectivity and disinhibition in individuals with Metabolic Syndrome

摘要

The global epidemic and major health problem of Metabolic Syndrome (MetS) is a composite of risk factors that together pose a greater risk for cardiovascular disease, diabetes, cognitive decline, and dementia than any of its individual risk factors alone. Individuals with MetS have decreased activity in the primary and secondary taste cortices. The primary taste cortex is involved in the identification and intensity of taste, while the secondary taste cortex is associated with the hedonics of taste, disinhibition, and decision making. Additionally, those with MetS have higher self-reported eating disinhibition levels. The present study used archival data to determine if functional connectivity of the primary and secondary taste cortices was altered in individuals with MetS and how that may affect eating disinhibition. The study was conducted using archival, pre-processed structural and functional MRI data on 26 individuals with MetS and 25 healthy controls. The Three-Factor Eating Questionnaire (TFEQ) was administered and contains eating behavior scores such as eating disinhibition. Functional connectivity was analyzed using psychophysiological interaction (PPI) methods to examine how brain regions interact with each other during a given task or stimulus. Individuals with MetS had significantly different functional connectivity of the primary and secondary taste cortices compared to those without MetS. Additionally, the relationship between the functional connectivity of the primary and secondary taste cortices was significantly correlated with eating disinhibition scores. However, there was no evidence to suggest that the activity of the secondary taste cortex mediated this relationship. Exploratory results also revealed significant altered functional connectivity of the primary taste cortex with brain regions associated with memory, reward, and emotion in individuals with MetS. The findings suggest that individuals with MetS compared to individuals without MetS have an altered functional connectivity of the taste cortices that is related to eating disinhibition. The present study elucidates the relationship of MetS, functional connectivity of the primary and secondary taste cortices, and eating disinhibition to better understand the symptoms and causes of MetS.