For decades, scientists have used these electrodes to listen in on individual brain cells in adult patients, uncovering remarkable things. Some neurons fire only when we recognise a familiar face. Others seem to represent entire concepts, lighting up whenever we think of a specific person or place, no matter how that person is described or shown to us. This kind of research has reshaped our understanding of memory, language and decision-making.

Yet almost none of it has included children. Bonda’s paper points out that while an estimated 250 children undergo this kind of invasive brain monitoring every year in the United States alone, only a handful of research teams have used the opportunity to study young, developing brains. In fact, only one study has ever looked at individual brain cells in children this way. That’s a striking gap, given that the brain changes dramatically as it grows, and findings drawn from adults can’t simply be assumed to apply to children.

But is it safe, and is it fair, to involve children in this kind of research? Bonda and his co-authors argue yes, carefully. The electrodes used for research are a fraction of a millimetre larger than the ones already needed for clinical care, and risks of implant are identical for both. Consent is handled with particular care: parents give permission, but children are also asked separately, in private, whether they want to take part, so they never feel pressured by a parent standing beside them. To keep young patients engaged during long hospital stays, the research tasks are turned into simple games, complete with scores and small prizes.

Bonda’s team frames this as more than a technical opportunity. They see it as a matter of fairness. Children have historically been left out of research that has transformed how we understand the human mind, even though many of them already have the electrodes in place. Extending this work to children, the authors argue, could eventually help us understand conditions like epilepsy, autism and ADHD from the inside, and ensure that young patients share in the benefits their own bodies help make possible.