Endovascular neural interfaces are devices delivered through the vascular system — typically via catheterization of the jugular vein — to position electrodes inside blood vessels adjacent to the brain. The approach leverages decades of endovascular neurology and interventional radiology techniques (stent placement, coil embolization) to access the brain without craniotomy or direct contact with neural tissue.

How It Works

The endovascular BCI procedure mirrors a routine neuro-interventional catheterization:

  1. A catheter is inserted into the jugular vein under fluoroscopic (X-ray) guidance
  2. The catheter is navigated through the venous system to the superior sagittal sinus — a large vein running along the midline of the brain, adjacent to the motor cortex
  3. The electrode-bearing stent (e.g., Synchron's Stentrode) is deployed within the vessel, where it self-expands and anchors to the vessel wall
  4. Over weeks, the vessel endothelializes around the stent, incorporating it into the vessel wall
  5. A lead wire connects the stent to a subclavicular receiver/transmitter unit implanted in the chest

Synchron Stentrode

Synchron's Stentrode is the only endovascular BCI to reach human clinical trials. It carries 16 electrode sensors on a self-expanding nitinol stent. Implanted in the superior sagittal sinus adjacent to motor cortex, the Stentrode records local field potentials and cortical activity through the vessel wall. In clinical trials (SWITCH, COMMAND), participants with ALS used the Stentrode to control computers for communication and daily tasks.

Advantages and Limitations

Advantages: No craniotomy, no direct brain contact, procedure similar to existing clinical stent placements, potentially lower infection risk, faster recovery.

Limitations: The blood vessel wall attenuates neural signals significantly. The Stentrode's 16 channels are far fewer than intracortical arrays (96-1,024 channels). Spatial resolution is limited by vessel anatomy — electrodes can only be placed where suitable veins exist near target brain regions. Signal quality is lower than subdural or intracortical recording, limiting the complexity of decodable neural commands.

Future Directions

Synchron demonstrated bidirectional endovascular BCI capability in 2026, adding stimulation to the recording-only Stentrode platform. Future generations may increase channel count and access additional brain regions via branching venous anatomy.