San Juan - It has happened to us more than once that we find ourselves in a hurry and the elevator we are waiting for takes too long to arrive. Immediately, we proceed to press the up or down key repeatedly, until we give up and decide to take the stairs. From a research perspective, the explanation for this fenomena of frustation was unknown until today. Guided by Drs. Fabricio Do Monte and Gregory Quirk, a team of neuroscientists in the School of Medicine at the University of Puerto Rico (UPR-RCM), discovered how the brain reacts to a frustrating event.