after soft. update, what is this spotlight feature from bottom of display?

Hi there,
I just did a software update (I'm running 10.6.8), and now my whole display is darker, because of a 'spotlight'-type look coming from the bottom of the screen... as if my screen is a stage, and these are spotlights shining on it.
I'd rather just have my screen brighter.
I don't know what this new 'feature' is called, so I don't know how to find and disable it. (I've been using the word spotlight, but I know that's the name of the Search tool, so googling that won't help me).
Can someone on this forum advise me?
Thanks,
malch

 

Hi Sim,
I just did a restart, and it's back to normal.
Thank you for your prompt offer to help though!
Regards,
malch