Four decades ago, studies have started pointing to sensory plasticity in the adult visual system, documenting surprising long-term improvements in perception. Such perceptual learning is enabled by repeated practice, inducing use-dependent plasticity in early visual areas and their readouts. I will discuss results from our lab challenging the fundamental assumption in perceptual learning that only 'practice makes perfect', indicating that brief reactivations of visual memories induce efficient rapid perceptual learning. Utilizing behavioral psychophysics, brain stimulation and neuroimaging, we aim to reveal the neurobehavioral mechanisms by which brief exposure to learned information modulates brain plasticity and supports rapid learning processes. In parallel, we investigate how these learning mechanisms operate across domains, for example by testing the hypothesis that similar inherent mechanisms may also result in maladaptive consequences, when brief reactivations occur spontaneously as intrusive enhanced memories following negative events. Unravelling the mechanisms of this new form of rapid learning could reshape learning theories across domains, setting the foundations to enhance learning in daily life when beneficial, and to downregulate maladaptive consequences of negative memories.