What do you mean "trigger". The interest rates that the Federal Reserve sets are done "manually". They don't rise and fall based on the supply or demand for money. If inflation (as measured by the Fed) increases and the Fed wants to lower it, they can decide to raise interest rates but it doesn't happen automatically.

According to this article [0], the Fed controls two of the three most important interest rates in the U.S. But if you look at their chart, all three rates have followed each other very closely since 2000. Although the Fed doesn't control the prime rate it seems that the prime rate doesn't deviate from what the Fed is doing very much.

[0] https://www.thebalance.com/what-interest-rates-does-the-fede...