Background: Proton Magnetic Resonance Spectroscopy (H-MRS) is a non-invasive imaging technique that enables quantification of neurochemistry in vivo and thereby facilitates investigation of the biochemical underpinnings of human cognitive variability. Studies in the field of cognitive spectroscopy have commonly focused on relationships between measures of N-acetyl aspartate (NAA), a surrogate marker of neuronal health and function, and broad measures of cognitive performance, such as IQ. Methodology/Principal Findings: In this study, we used H-MRS to interrogate single-voxels in occipitoparietal and frontal cortex, in parallel with assessments of psychometric intelligence, in a sample of 40 healthy adult participants. We found correlations between NAA and IQ that were within the range reported in previous studies. However, the magnitude of these effects was significantly modulated by the stringency of data screening and the extent to which outlying values contributed to statistical analyses. Conclusions/Significance: H-MRS offers a sensitive tool for assessing neurochemistry non-invasively, yet the relationships between brain metabolites and broad aspects of human behavior such as IQ are subtle. We highlight the need to develop an increasingly rigorous analytical and interpretive framework for collecting and reporting data obtained from cognitive spectroscopy studies of this kind.
Bibliographical note© 2014 Patel, Blyth, Griffiths, Kelly and Talcott. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Funding: Engineering and Physical Sciences Research Council 
- proton magnetic resonance spectroscopy
- N-acetyl aspartate
- processing speed
- cognitive spectroscopy
Student thesis: Doctoral Thesis › Doctor of Philosophy
Patel, T., Blyth, J. C., Griffiths, G., Kelly, D., & Talcott, J. B. (2014). Moderate relationships between NAA and cognitive ability in healthy adults: implications for cognitive spectroscopy. Frontiers in Human Neuroscience, 8, . https://doi.org/10.3389/fnhum.2014.00039