on the brain
Meaning
on the brain
(idiomatic) Obsessively in mind.
He's only got one thing on the brain: lust.
Examples
Money is the last enemy that shall never be subdued. While there is flesh there is money or the want of money, but money is always on the brain so long as there is a brain in reasonable order.
Whatever we cannot easily understand we call God; this saves much wear and tear on the brain tissues.
Our spirit is not dependent on the brain or body. It is eternal, and no one has one sentence worth of hard evidence that it isn't.
American diplomacy is easy on the brain but hell on the feet.
We have, as a result of two thousand years of Christianity, sex on the brain. Which isn't always the best place for it.
Independence is a heady draught, and if you drink it in your youth, it can have the same effect on the brain as young wine does. It does not matter that its taste is not always appealing. It is addictive and with each drink you want more.