Mose created his version of the old blues tune "My Babe". The last line is not clear. Could someone help me out?

My brain is always workin', my brain.
My brain is always workin', my brain.
My brain is always workin',
Long as you keep that coffee perkin'
My brain, Cool little _____?, My brain.

My brain is always tickin', my brain.
Long as I'm alive and kickin'.

My brain is losin' power, my brain.
Several hundred neurons every hour.

My brain is gettin' pounded, my brain.
Purty soon I'll be dumbfounded.

Each verse ends with "My brain, cool little _______?, My brain."

Cool little what?