I have performed a random effects analysis on a parametrically modulated (by normalized reaction times) regressor, which resulted in one significant cluster. I would like to show a graph that represents the results in the cluster (or peak voxel) with reaction time on the x-axis and bold response on the y-axis. I have two questions regarding making this graph:

1) when I display the contrast image (from the random effects), is the "intensity" value the average slope?

2) How can I extract the values for the y-axis (y-intercept) and what would be the units for the y-axis?