These maps show the number of repeats in a "jackknife" analysis that voxels remained significant in. A jackknife analysis runs a meta-analysis as many times as there are studies, leaving one study out each time. This gives a measure of reliability. For all maps, maximum replicability would show as a value of 12.
These maps are in .nii format so can be opened in many neuroimaging viewers. If you do not have a viewer installed, one free option is MRIcron which can be downloaded from www.nitrc.org/projects/mricron. They can also be viewed online through NeuroVault, see the third link in "references" below.
Links to the paper can be found in the references section below: 1) On NeuroImage 2) Open access version on the Social Decision Lab website.
The decision to share resources is fundamental for cohesive societies. Humans can be motivated to give for many reasons. Some generosity incurs a definite cost, with no extrinsic reward to the act, but instead provides intrinsic satisfaction (labelled here as ‘altruistic’ giving). Other giving behaviours are done with the prospect of improving one's own situation via reciprocity, reputation, or public good (labelled here as ‘strategic’ giving). These contexts differ in the source, certainty, and timing of rewards as well as the inferences made about others' mental states. We executed a combined statistical map and coordinate-based fMRI meta-analysis of decisions to give (36 studies, 1150 participants). Methods included a novel approach for accommodating variable signal dropout between studies in meta-analysis. Results reveal consistent, cross-paradigm neural correlates of each decision type, commonalities, and informative differences. Relative to being selfish, altruistic and strategic giving activate overlapping reward networks. However, strategic decisions showed greater activity in striatal regions than altruistic choices. Altruistic giving, more than strategic, activated subgenual anterior cingulate cortex (sgACC). Ventromedial prefrontal cortex (vmPFC) is consistently involved during generous decisions and processing across a posterior to anterior axis differentiates the altruistic/strategic context. Posterior vmPFC was preferentially recruited during altruistic decisions. Regions of the ‘social brain’ showed distinct patterns of activity between choice types, reflecting the different use of theory of mind in the two contexts. We provide the consistent neural correlates of decisions to give, and show that many will depend on the source of incentives.