Risks of developing mild cognitive impairment (MCI) and Alzheimer’s disease (AD) are directly correlated to, yet not exclusively dependent on, age-related factors. Such physiological factors include the accumulation of proteins amyloid-beta and tau, decreased cerebral blood flow, exacerbated neuroinflammation and microglial response, and decreased brain glucose metabolism. Taken together, these age- and disease-related factors eventually impact cognitive performance, the most clinically significant output in the study of age-related disorders. Proton magnetic resonance spectroscopy (1H-MRS), an MR-based technology that allows in vivo estimation of brain metabolites, has demonstrated valuable input in the study of aging and AD. Metabolites estimated with 1H-MRS act as neurotransmitters, osmolytes or energetic compounds and maybe thus be interpreted as proxy markers of age- or disease-related physiological phenomena such as neuronal loss and degeneration (NAA), inflammation (Cho, mI, Glu) and cellular metabolism (Cr, PCr). Furthermore, 1H-MRS obtained at higher fields (B0>3T) can reliably estimate compounds such as glutathione, glutamate and lactate, suggesting its constant technical evolution and relevance in the field. However, 1H-MRS-derived information critically needs to be put in perspective with other imaging indices to fully comprehend its added value to the study of normal and pathological aging.
The goal of the collection is to highlight works in multimodal imaging combining 1H-MRS and other imaging methods (DWI, fMRI, PET, EGG, etc.) in the study of healthy and pathological aging, with a focus on identifying novel biomarkers and correlates of cognitive decline. The specific aims of the Research Topic are, in order of importance, 1) to assess relationships between 1H-MRS neurochemistry and cognitive decline in healthy and pathological aging, 2) to assess possible relationships with 1H-MRS and measures of inflammation, brain energetics, cerebral connectivity and blood flow, and 3) to identify future directions in MRS and multimodal imaging in the study of aging.
Therefore, the types of articles that will be prioritised in the Research Topic are:
• Original research; in MRS or multimodal imaging with MRS in healthy or pathological aging.
• Reviews; in MRS in healthy or pathological aging, with a preference for AD/MCI, inflammation, cerebral blood flow, general cognition, as additional subtopic (one of these).
• Methods; providing technical outlines for MRS-based multimodal imaging in the study of healthy or pathological aging.
The Guest Topic Editors are indebted to the critical contribution made by
William Vallet in coordinating the launch of this Research Topic.