To insert a title to the colorbar in matlab.
Use the following code (Source):
% Loads a data for the example
load mandrill
% Plots an image for the example
image(X)
% Inserts a colorbar. a handle is created
t=colorbar;
% sets the ylabel property of the handle t.
set(get(t,'ylabel'),'string','My colorbar title','Fontsize',10)