is there a shortcut to expand folders in Finder while being in Cover Flow mode?

in Finder I can use the arrow keys to go up and down and with "left arrow" and "right arrow" I can expand a folder while being in List View mode. However, when I'm in Cover Flow mode the "left arrow" and "right arrow" do the same as "up arrow" and "down arrow", i.e. just go up and down in the list. How can I expand a folder while being in Cover Flow?