Pat Kenny is joined by Prof Luke O’Neill to unpack two striking breakthroughs in brain science, starting with the Nobel Prize-winning technology that uses light to switch neurons on and off. From an algae protein to moving a mouse’s whiskers with a beam of light, they explore how this tool could transform how we study the living brain — and what it might mean for restoring sight or even tackling epilepsy. They also discuss the unsettling-but-promising work of growing human brain tissue from skin cells and wiring it into a mouse brain, opening new ways to study conditions like cerebral palsy.