Brain Game: That's What It's For

The goal of each mentalfloss.com Brain Game challenge is to get your noggin active. This week's Wednesday Wordplay puzzle is a word ladder with just that in mind. Here you go:

By changing one letter in each step to form English words, and leaving all other letters in their original positions, convert BRAIN into THINK in the fewest possible steps.

B R A I N
_ _ _ _ _
_ _ _ _ _
_ _ _ _ _
_ _ _ _ _
_ _ _ _ _
_ _ _ _ _
T H I N K