grey matter
gray matter
grey substance
gray substance
substantia grisea

I think you must be missing some grey matter too.

There had been entirely too much traffic through my gray matter of late and I was not looking forward to any more.

How long has it been since people added three numbers like 47, 24 and 3 using nothing but gray matter?

It just requires a little time and activity from the old grey matter.

After all, except for gray matter, she had no flesh.

Women on average have a higher percentage of gray matter in comparison to men.

A section through the material also appeared to show grey and white matter.

Little grey matter's all you want to remember things with.

There are a few others but grey matter letting me down these days.

The back of her head was thick with blood and gray matter.