Yiyuan Tang, Pegah Askari, Changho ChoiMindfulness training (MT) involves paying attention to the present and increasing awareness of one’s thoughts and emotions without judgment and has become a promising intervention for promoting health and well-being. Neuroimaging studies have shown its beneficial effects on brain functional activity, connectivity, and structures [1-3]. A series of RCTs indicated that one form of MT, integrative body-mind training (IBMT) induces brain functional and structural changes in region related to self-control networks such as the anterior cingulate cortex (ACC) after 2-10 h of practice [1-3]. However, whether MT could change brain metabolism in the ACC remains unexplored. Utilizing a non-invasive proton magnetic resonance spectroscopy (MRS), we conducted the first pilot study investigating whether brief IBMT could change the excitatory and inhibitory responses of neurotransmitters within the ACC [1-3]. Nine healthy college students completed ten 1-hour IBMT sessions within 2-week and brain metabolism were assessed before and after using a 3T Siemens Prisma scanner. Following survey imaging and T1-weighted structural imaging, single-voxel point-resolved spectroscopy (PRESS) was conducted for estimating the metabolite concentrations in 2 regions - rostral and dorsal ACC based on prior literature [1-4]. PRESS scan parameters included TR 2s, TE 90 ms, sweep width 2.5 kHz, 1024 sampling points, and 256 signal averages. Water suppression and B0 shimming up to second order were performed with the vendor- supplied tools. Reference water signal was acquired for eddy current compensation, multi-channel combination, and metabolite quantification. Spectral fitting was performed with LCModel software [5], using in-house basis spectra of metabolites which were calculated incorporating the PRESS slice selective RF and gradient pulses. The spectral fitting was performed between 0.5-4.0 ppm. After correcting the LCModel estimates of metabolite signals for the T2 relaxation effects using published T2 values [6], the millimolar concentrations of metabolites were calculated with reference to water at 42 M. Paired t-tests were performed to examine changes. Results indicated a significant increase in glutamate metabolism (t = 3.24, p=0.012), as well as Glx (glutamate + glutamine) (t = 2.44, p=0.041) in the rostral ACC. Results indicate that MT may not only increase ACC activity, but also may induce neurochemical changes in regions of self-control networks, suggesting a potential mechanism of MT’s effects on disorders such as addiction and schizophrenia, which often involve the dysfunction of glutamatergic system (i.e. lower glutamate metabolism).References1\. Tang YY, Holzel BK, Posner MI. The neuroscience of mindfulness meditation. Nat Rev Neurosci 2015, 16: 213-222\. Tang YY. The Neuroscience of Mindfulness Meditation: How the Body and Mind Work Together to Change Our Behavior? Springer Nature, 20173\. Tang YY, Tang R, Gross JJ. Promoting emotional well-being through an evidence-based mindfulness training program. Front Hum Neurosci. 2019, 13:2374\. Yang S et al. Lower glutamate levels in rostral anterior cingulate of chronic cocaine users - A (1)H-MRS study using TE-averaged PRESS at 3T. Psychiatry Res. 2009, 174:171-65\. Provencher SW. Estimation of metabolite concentrations from localized in vivo proton NMR spectra. Magn Reson Med. 1993, 30:672–6796\. Ganji SK et al. T2 measurement of J-coupled metabolites in the human brain at 3 T. NMR Biomed. 2012, 25: 523–529