Because loving kindness overlaps with other forms of meditation from the Theravada/insight tradition in the practice of “letting go” of the conceptual self, it is likely and difficult to ascertain how experience in these other practices influences loving kindness. Even with a smaller number of reported hours of loving

kindness, meditators may practice loving kindness in a selfless manner as compared to novices based on their many hours spent practicing other forms of meditation from this tradition. This finding may be of particular relevance to understanding the commonalities between different meditation practices, and is supported empirically by the findings Inhibitors,research,lifescience,medical of this study. These confounds can be addressed in studies comparing the neural substrate of different meditation

practices in meditators; this study was underpowered to make such comparisons. Future studies should also track changes in the Inhibitors,research,lifescience,medical neural substrate of loving kindness and other meditation practices across training. Future work may also test the see more relationship between these findings and behavioral or clinical measures such as compassionate behavior (Condon et al. 2013). Acknowledgments We thank our participants Inhibitors,research,lifescience,medical for their time and effort; Joseph Goldstein and Ginny Morgan for input on meditation instructions; Jeremy Gray and Hedy Kober for input on study design; Thomas Thornhill IV for study coordination; Susan Whitfield-Gabrieli and Carlo de los Angeles for their input on data analysis; Aneesha Ahluwalia for her input on the manuscript; and Hedy Sarofin and Inhibitors,research,lifescience,medical staff of the Yale Magnetic Resonance Research Center for their contributions.

Conflict of Interest None declared. Supporting Information Additional Supporting Information may be found in the online version of this article: Figure S1. All slices are displayed for the comparison of BOLD signal during loving kindness meditation between meditators and novices, corresponding to Fig. ​Fig.1.1. Brain regions in blue/cold show reduced BOLD signal during loving kindness meditation in meditators as compared Inhibitors,research,lifescience,medical to novices (P < 0.05 FWE, cluster corrected; slices displayed left to right). Figure S2. All slices are displayed for the comparison of intrinsic connectivity during loving kindness meditation between meditators and novices, corresponding to Fig. ​Fig.2.2. Brain regions in blue/cold show less intrinsic connectivity during ever loving kindness meditation in meditators as compared to novices (P < 0.05 FWE, cluster corrected; slices displayed left to right). Figure S3. All slices are displayed for the comparison of seed-based functional connectivity during loving kindness meditation for novices greater than meditators. Brain regions in yellow/hot show greater functional connectivity with the posterior cingulate cortex/precuneus during loving kindness meditation in novices than meditators (P < 0.