LORETA 3-Dimensional Source Correlations
NeuroGuide computes the Pearson Product Correlation Coefficient (-1 to +1) with respect to a 3-dimensional Region of Interest (ROI) and the remainder of the 2,394 LORETA Gray Matter Pixels and then displays the results in the LORETA Viewer (see NeuroGuide Manual Appendix-G). The ROI is identified by either an Anatomical Name or by Brodmann Area. The average current sources of the ROI are used in the computation of the correlation coefficient and the ROI correlation with itself = 0 in the LORETA Viewer.
Brodmann assigned numbers to various cortical regions by analyzing each area's cellular structure starting from the central sulcus (Area No. 1). Different cell structures resulted in different Brodmann area numbers. Below are illustrations of the Brodmann areas for the lateral sagital surface of the cortex as well as the medial surface. Use the illustrations below to aid in deciding which Brodman areas and/or anatomical locations to be selected in NeuroGuide.
After the LORETA Viewer Launches Click ScaleWin and Adjust the Change Max Wiper to the correlation value that is statistically significant based on the Degrees of Freedom (i.e., number of 2 second epochs or the edit time in seconds divided by 2). Then click Time Frame arrows to advance from 1 to 30 Hz and view the correlations between, e.g., the Right Inferior Temporal Gyrus and the remainder of the 2,394 pixels.