importance of data discoverability: an informatics issue that was not considered by WWARN's designers in the initial phase, when it was assumed that access for external users would be limited to the summary data shown on the WWARN Explorer. Discoverability - the ability of potential outside users to find the data set and easily understand what it contains - is critical if the data are to be reused by any investigator with a legitimate research question that may be addressed by data held in the resource. WWARN took care to develop data management tools that included a full audit trail for the variables that they standardised.

(B) Dyn labeling in dyn-IRES-cre x Ai9-tdTomato compared to in situ images from the Allen Institute for Brain Science in a sagittal section highlighting presence of dyn in the striatum, the hippocampus, BNST, amygdala, hippocampus, and substantia nigra. All images show tdTomato (red) and Nissl (blue) staining.(C) Coronal section highlighting dynorphinergic cell labeling in the NAc as compared to the Allen Institute for Brain Science.

Because cue-evoked DA release developed throughout learning, we examined whether DA release correlated with conditioned-approach behavior. Figure 1E and table S1 show that the ratio of the CS-related DA release to the reward-related DA release was significantly (r2 = 0.68; P = 0.0005) correlated with number of CS nosepokes in a conditioning session (also see fig. S4).

Data reuse. Respondents were asked to indicate whether they have the sole responsibility for approving access to their data. Of those who answered this question, 43% (n=545) have the sole responsibility for all their datasets, 37% (n=466) have for some of their datasets, and 21% (n=266) do not have the sole responsibility.