This is the first synthetic biological intelligence experiment that shows neurons can adjust their activity to perform a specific task – and, when provided with feedback, can learn to perform that task better."The beautiful and pioneering aspect of this work rests on equipping the neurons with sensations – the feedback – and crucially the ability to act on their world," says theoretical neuroscientist Karl Friston of University College London in the UK.A few years ago, Friston developed a theory called the free energy principle, which proposes all biological systems behave in ways that reduce the gap between what is expected and what is experienced – in other words, to make the world more predictable."The translational potential of this work is truly exciting: it means we don't have to worry about creating 'digital twins' to test therapeutic interventions," says Friston."We're trying to create a dose response curve with ethanol – basically get them 'drunk' and see if they play the game more poorly, just as when people drink," Kagan says."