This year’s Nobel Prize in Physiology or Medicine recognizes optogenetics, a groundbreaking method that has revolutionized brain research. Swedish newspaper *Dagens Nyheter*'s science reporter, Johan Nilsson, explains the significance of the prize and its potential impact on future research. Optogenetics allows scientists to control nerve cells using light, offering unprecedented precision in studying brain functions. The discovery could have far-reaching implications for understanding and treating neurological and psychiatric disorders. Nilsson discusses how these findings may contribute to advancements in the treatment of conditions like Parkinson’s disease and depression. The Nobel committee highlighted the potential of optogenetics to transform our understanding of the brain and its complexities. This prize acknowledges the pioneering work that has opened new avenues for neuroscience research in Sweden and globally.