Sparking Trouble: Why Brain Stimulation Isn't a One-Size-Fits-All Cure

Transcranial direct current stimulation (tDCS) has long been the darling of experimental neuroscience, promising to boost cognitive function with a gentle electrical nudge. However, new research suggests that in neurodevelopmental conditions like Angelman syndrome (AS), this nudge may act less like a helping hand and more like a runaway train.

In a rigorous study examining the parietal cortex of mice, researchers applied repeated anodal tDCS over five days. The results were telling. While healthy ‘wild-type’ mice displayed a robust capacity for homeostatic regulation—effectively dialling down their internal volume to counter the external electrical boost—the AS models faltered. Their neurons exhibited a dysregulated surge in excitability, lacking the compensatory mechanisms required to maintain balance at both the intrinsic and synaptic levels.

Crucially, this electrical storm did not translate into cognitive gain. Neither group saw improvements in spatial memory, although exploratory behaviour was altered. The findings underscore a critical biological constraint: the brain’s response to stimulation is heavily dependent on its underlying neurobiological context. In a disordered system where synaptic brakes are faulty, standard stimulation protocols might exacerbate instability rather than correct it. As we look toward clinical applications, this serves as a stark reminder that generic electrical therapies require rigorous personalisation.