DeepPLL: Synchronization of non-invasive brain stimulation to deep brain stimulation

Deep brain stimulation (DBS) is increasingly viewed as a network-level intervention, yet clinical practice typically targets a single brain structure per hemisphere. Coordinated multi-site stimulation may help probe and modulate distributed circuits, but additional invasive implantation is limited by safety and ethical constraints. Here, we present an approach to couple DBS with non-invasive transcranial alternating current stimulation (tACS) via precise phase synchronization. We introduce DeepPLL, an open-source interface device enabling real-time phase locking between DBS pulse trains and external stimulation like tACS. The system extracts DBS EEG artefacts using an isolated analogue front