are you asking about the scrolling buttons fixed to the scroll bar or the additional buttons in the Control Bar?
The scroll arrows at the ends of the scrollbar are gone since MacOS X Lion. There is no way to reactivate them in Aperture. However, you can show the Control Bar in Aperture. It has stepping arrows.
Window > Show Control Bar.
I had forgotten about that --- but I was looking for, unfortunately, the scrollbar thing that was in Aperture and now is apparently gone...I guess I'll have to get used to using the scroll button on the R side to slide up and down or the keystroke [which is what I usually do to move thru pics] or the control bar....but I liked working with the arrows [up and down] because then I could move at my own pace....thanks for answering.
You could use the keyboard shortcuts tied to the buttons instead, if you like.
If you hover the mouse over one of the buttons, you will see the available shortcuts:
Also the arrow keys are working well.
Does your mac have a trackpad? If not, would be a good idea to get one. I don't use the scrollbar much, since I got a trackpad. Scrolling is much more convenient with gestures on the Trackpad - simply move the fingertips a bit. No more mouse cables wrapped around my coffee mug.
Thanks for the ideas - I'll check for the keystroke = I use a Logitech ergo mouse and it and its scroll wheel work fine and the buttons and shortcuts above would work as well = I just got used to being able to keep the mouse on the upper or lower triangle button and scroll up and down without moving - it just worked better for me = but I'll check out your ideas == I have an older MacPro and tried a Trackpad with it and didn't work so well so I might stick with what does work now, since I don't use it for graphics and Aperture all the time = again, many thanks.