Analysis of functional magnetic resonance imaging (fMRI) data is becoming ever more computationally demanding as temporal and spatial resolutions improve, and large, publicly available data sets proliferate. Moreover, methodological improvements in the neuroimaging pipeline, such as non-linear spatial normalization, non-parametric permutation tests and Bayesian Markov Chain Monte Carlo approaches, can dramatically increase the computational burden. Here, we therefore present BROCCOLI, a free software package written in OpenCL (Open Computing Language) that can be used for parallel analysis of fMRI data on a large variety of hardware configurations. BROCCOLI (running on a GPU) can perform non-linear spatial normalization to a 1 mm brain template in 4–6 s, and run a second level permutation test with 10,000 permutations in about a minute. The new software is freely available under GNU GPL3 and can be downloaded from github (https://github.com/wanderine/BROCCOLI/).
GNU General Public License (GPL)
The GNU General Public License; see: http://www.gnu.org/copyleft/gpl.html
The GPL requires that source code to a tool or resource be made available, and that modified versions of the tool or resource (including new tools which include part of the original tool's source) make the modified source available to users.
A developer of a tool or resource distributed under the GPL ensures that users of the tool and of modified versions of the tool may always inspect the source code and modify the source to suit their needs, and that users may modify the tool as they see fit without being obliged to distribute their changes. While this may seem to encourage multiple versions of the same tool, the result is often that changes are passed back to the tool originator and incorporated into the original tool.