Regional variations in cingulate cortex glutamate levels: A magnetic resonance spectroscopy study at 3T.
Academic Article
Overview
abstract
Regional variations in glutamate levels across the cingulate cortex, decreasing rostral-to-caudal, have been observed previously in healthy volunteers using proton magnetic resonance spectroscopy (1H-MRS) at 7T. This study sought to explore cingulate cortex glutamate trends further by investigating whether a similar gradient could be detected at 3T, the effect of sex, as well as whether individual variations gave rise to more than one regional glutamate pattern. 1H-MRS at 3T (Phillips Elition, semi-Localization by Adiabatic Selective Refocusing, TE/TR = 32/5000) was acquired in four cingulate regions: the anterior, mid-anterior, mid-posterior, and posterior cortices, in 50 healthy participants (26F) scanned at a fixed time of day and with controlled food intake. K-means clustering was used to characterize the presence of distinct regional patterns, which were then compared between sex and clusters. In addition, cortical thickness was compared between clusters, and in relation to glutamate. Aligned with 7T findings, we demonstrated that average glutamate levels decreased rostral-to-caudal in the healthy cingulate cortex. No effect of sex was found, suggesting similar resting glutamate levels in both sexes. Interestingly, the majority of participants were characterized by glutamate levels that did not significantly change across the cingulate (65%). Different regional patterns in cortical thickness between clusters offer further evidence into these distinct glutamate variations and suggest both a neuroanatomical and functional role may lead to these findings. This study provides a much needed foundation for further research to determine the implications of neurotransmission patterns in health and disease.
