Novel Methods for the Visualization and Analysis of Functional Maps in Cortex

Flat Maps 23 Since the distances cannot be matched perfectly, some distortions are introduced in the un- folding process. To improve the precision, only a region of interest rather than an entire hemi- sphere is sometimes flattened. Once the unfolding process has finished, the former folded sheet, which spanned several image planes, can be viewed in a single image (Figure 9). It is possible to overlay functional data onto anatomical data (explained in the following sections). This provides a good over- view of the organization across the cortical surface. Section 3.8 explains different types of flat maps in more detail. For further information on flat maps and their creation, please refer to [Wandell, 1999 #16] [Teo, et al., 1997 #8] [Wandell, et al., 2000 #38] [Floater, 1997 #39]. Figure 8: Nodes and Delaunay triangulation Initial planar positions of the nodes with Delaunay triangulation (a) and positions of the nodes after adjusting the node positions (b) to match distances between two corresponding nodes in the plane and in three-space better; Source: [Wandell, et al., 2000 #38] (a) (b)