The purpose of the ICBM brain template is to provide a reference that includes both a set of coordinates and the associated anatomical labels. The localization of functional imaging results on averages of large number of brain MRI volumes does not provide detailed anatomical information. Alternatively, the spatial registration and normalization of brain images from different individuals to a single high-resolution labeled template recognizes the topographically relevant anatomical substrate for a specific activation.
The ICBM (International Consortium for Brain Mapping) high-resolution single subject template is aligned with the individual subject T1 whole brain MRI provided. An AIR nonlinear warp, a 5th order polynomial, is used for this fit. The demarcated labels on the template are then resampled through the warp transform to the subject MRI. A nearest-neighbor resampling is used to ensure the labels stay as labels. The 0.125mm3 resolution of the template helps ensure that the proper label, at least according to the transform, is used in the resampling.
The volumes are in minc format and can presently be visualized using the program Display. To view both the structural MRI and the labels launch the program typing Display icbm_template.mnc -label icbm_labels_corrected.mnc. The opacity of the labels can be set in the Colour Coding menu. The number of each label appears at the bottom left of the orthogonal views window. This number corresponds to a unique structure as listed in the table provided (labels_text).
The following paragraphs describe the methods that were used on the different version(s) of the ICBM Template.
The high definition structural brain template is the average of 27 T1 weighted MRI acquisitions from a single subject (from Montreal Neurological Institute database). The template is aligned within the stereotaxic space of the ICBM average template derived from that of Talairach and Tournoux (1988). Cortical gyri, subcortical structures and the cerebellum have been delineated from the structural brain template and assigned a unique label.
The 3-D set of labels can be imported and registered onto the structural MRI of any individual subject through software like BrainSuite
Additional information about this atlas is available at the following resources:http://dx.doi.org/10.1006/nimg.1995.1012http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1088516/http://www.ncbi.nlm.nih.gov/pubmed/11522763http://www.ncbi.nlm.nih.gov/pubmed/17266101