Since Brodmann's description of the distinct histological segmentation of the brain cortex, the main focus of research has been to study and describe functions associated to single brain areas. However, both clinical and modern neuroimaging studies have demonstrated that complex brain functions are the result of a network interaction. The Brodmann's Areas Connectivity Map is intended to provide a basic background to understand brain functional connectivity by characterizing basic networks utilizing the Brodmann's nomenclature.
Connectivity map was conducted in a single 21-y-o right handed female, whose functional and anatomical data were obtained from the free database on resting-state fMRI available at NITRC.org (http://www.nitrc.org/frs/?group_id=296). Specifically, we chose the study No.10958 from the data uploaded by the Department of Radiology of Oulu University Hospital, Oulu, Finland.
BOLD fMRI resting-state consisted of 245 volumes with imaging parameters as follows: whole-brain single-shot EPI T2* BOLD scans acquired axially, TR/TE = 1800/45 ms; FA = 90; FOV = 240; 28 slices; matrix = 64 x 64, voxel size = 3.75 mm x 3.75 mm x 4 mm. The subject's high resolution T1 3D-MRI image was utilized for initial co-registration of the functional networks and further normalization to MNI template.
Connectivity maps were obtained utilizing CONN tool box ( http://www.nitrc.org/projects/conn) running under Matlab 7.7 (2008) (http://www.mathworks.com). Results were filtered to 0.01 to 0.1 Hz to limit spatial-temporal correlation to the spontaneous brain oscillation power; Brodmann’s areas ROIs provided by the same tool were utilized as seeding areas. Analysis included as confounds CSF variations and signal drifting. Each Broadmann region was analyzed against all other Broadmann regions. The output resulted in connectivity matrices for both left and right hemispheres.
The mosaics of transversal images oriented with neurological convention were constructed with a script developed using Imagemagick (http://www.imagemagick.org/script/index.php) and displayed with MySQL (http://www.mysql.com/) software. Two mosaics were generated for each Brodmann’s area, one for the left and one for the right hemisphere. To create the mosaics, fMRI resting-state data were overlaid on the high resolution MNI template. All maps were thresholded initially to p < 0.01 corrected. However the threshold was manually increased to remove "activations" appearing in non-neural structures (e.g.: ventricles, isolated white matter). From these images, we selected nine slices, equally spaced in the axial plane to represent the entire volume. We then combined the nine slices to create a single 3 x 3 mosaic. For consistency purposes, the same slices were selected for each mosaic across hemispheres and Brodmann’s areas. All smoothed values from each Brodmann’s area connectivity matrix and corresponding maps were imported to tables in a MySQL database. Results were correlated with well established clinical findings.
Christian Broce, BA, web designer, for his contribution implementing this site. Dr. Nolan Altman, MD., chief of the Radiology Department, and Mr. Jose Perdomo, MCH's Research Director, for their support.
The "Brodmann's area Connectivity Map - Interactive Atlas" page utilizes the brain template and Brodmann's segmentation included in SPM8, (http://www.fil.ion.ucl.ac.uk/spm/). Brodmann's segmentation is approximate since it is not anatomical based. Caution is advised.