AFNI is a blanket term for a software program and myriad of plug-ins coded in the C programming language for the purpose of functional Magnetic Resonance Imaging (fMRI) analysis. It is able to run naively on Unix with X11 and Motif; and has been operated with limited success using Cygwin (according to User:Bradley Monakhos) AFNI's unofficial backronym is Analysis of Functional Neural Images. AFNI is distributed under an open-source license and is free to download and use for brain imaging research.