Endovascular electrode array (Stentrode)

The endovascular electrode array reaches the brain through its blood vessels: a stent-mounted electrode array (the Stentrode is the best-known instance) is delivered by catheter through the jugular vein and lodged in a cortical draining vein, typically the superior sagittal sinus over motor cortex, where it endothelialises into the vessel wall. It records field potentials from adjacent cortex without a craniotomy, using the neurointerventional techniques already routine for stroke and aneurysm treatment.

Signal quality sits between scalp EEG and subdural ECoG: the vessel wall and blood add some distance and attenuation relative to surface electrodes, but the array is intracranial and mechanically stable, and first-in-human studies have shown people with paralysis controlling digital devices. Open questions include the achievable channel count within a vessel, long-term thrombosis and vessel-health risk, whether it can ever support stimulation, and how its bandwidth compares with cortical-surface arrays over years.