  Sophisticated visualization tools are essential for the presentation and
exploration of human neuroimaging data. While two-dimensional orthogonal views
of neuroimaging data are conventionally used to display activity and
statistical analysis, three-dimensional (3D) representation is useful for
showing the spatial distribution of a functional network, as well as its
temporal evolution. For these purposes, there is currently no open-source, 3D
neuroimaging tool that can simultaneously visualize desired combinations of
MRI, CT, EEG, MEG, fMRI, PET, and intracranial EEG (i.e., ECoG, depth
electrodes, and DBS). Here we present the Multi-Modal Visualization Tool
(MMVT), which is designed for researchers to interact with their neuroimaging
functional and anatomical data through simultaneous visualization of these
existing imaging modalities. MMVT contains two separate modules: The first
includes complete stand-alone pre-processing pipelines, from raw data to
statistical maps. The second module is an add-on to the open-source,
3D-rendering program Blender. It is an interactive graphical interface that
enables users to simultaneously visualize multi-modality functional and
statistical data on the cortex and in subcortical surfaces as well as the
activity of invasive electrodes. This tool also enables highly accurate 3D
visualization of neuroanatomy, including the location of invasive electrodes
relative to brain structures. Each of the modules and module features can be
integrated, separate from the tool, into existing data pipelines. MMVT
leverages open-source software to build a comprehensive tool for data
visualization and exploration This gives the tool a distinct advantage in both
clinical and research domains as each has highly specialized visual and
processing needs.
