During the early 1960s researchers advanced experimental neuromodulation by applying targeted electrical stimulation to the brain, reliably evoking motor, sensory, or perceptual responses in humans and animals. The period emphasized cortical mapping through evoked responses and the exploration of plasticity by repeated stimulation, creating methodological foundations for neuromodulation studies and raising early ethical considerations. The field coalesced around direct stimulation techniques, intracranial self-stimulation concepts, and systematic measurement of neural and behavioral outcomes, unifying diverse lines of inquiry into a coherent paradigm.