TechnologyHow do neural interfaces work?
How we interface with the nervous system
Every neural interface trades access, resolution and invasiveness against each other. This explorer places 32 of them on one map, by what they do and how far they have come, so that an EEG cap, a deep brain stimulator and an intracortical array can be read on the same terms.
BCI is evolving from decoding the nervous system to interacting with it.
- Reading
- Writing
- Closed loop
- Biohybrid
32 interfaces
Read
Bidirectional
Write
Non-invasive
Around the head
On the skin
Minimally invasive
Vessel or skull window
Invasive
Nerve or sense organ
On the cortex
In the cortex
Deep brain
Biohybrid · Adjacent frontier
Living neural tissue outside the body. Not an interface with a person.
Colour · function
- Read
- Write
- Bidirectional
- Biohybrid
Fill · maturity as a clinical modality
- Established
- Human feasibility
- Early human
- Preclinical
- Research frontier
- Adjacent frontier
WriteInvasiveElectrical
Deep brain stimulation
Leads implanted in deep nuclei deliver continuous electrical pulses from a generator under the skin. It is the most widely used implanted brain stimulation therapy.
Showing Deep brain stimulation: Write, Invasive.
- Where it acts
- Leads in deep nuclei, such as the subthalamic nucleus
- Information flow
- Implanted lead → deep target
How far it has come
- As a clinical modality
- EstablishedAn authorised treatment for Parkinson's disease, essential tremor, dystonia and epilepsy.
- As a BCI application
- Early humanConventional systems stimulate without reading. The closed-loop form is sensing-enabled DBS.
- Access
- Invasive
- Mechanism
- Electrical
- Target
- Deep brain
- Signal
- Continuous electrical pulses
Characteristics · write interfaces
- Spatial precisionA few millimetres around each contact
- Temporal precisionMillisecond pulses
- Penetration depthAny depth, by surgery
- TargetabilityA chosen nucleus; directional contacts
- CoverageOne or two targets
- InvasivenessStereotactic brain surgery
- ReversibilityCan be switched off; the lead stays
Each track runs from low to high. A wide bar means the characteristic varies across implementations.
Strengths
- Decades of clinical use and long-term data
- Adjustable, and can be switched off
Trade-offs
- Brain surgery, with a small risk of bleeding and infection
- Conventional systems stimulate continuously, whatever the brain is doing
Common applications
- Parkinson's disease
- Essential tremor and dystonia
- Epilepsy
- Research in depression and obsessive-compulsive disorder
Human evidence
Extensive: randomised trials and decades of routine care for movement disorders.
What needs to happen next
Stimulation that adapts to measured brain state, and controlled evidence in psychiatric conditions.
- Same site, other direction
- Use cases
- Restore
- Patent activity
- 240 patent families name this interface, most often on stimulation, electrodes and arrays, closed loop. The patent landscape
Descriptions, ranges and maturity levels are editorial analysis, kept qualitative where the literature does not support exact comparison across technologies. Specific devices differ.
All 32 interfaces as a table
| Interface | Function | Access | Mechanism | Target | Clinical modality | BCI application |
|---|---|---|---|---|---|---|
| Read | Non-invasive | Electrical | Cortex | Established | Human feasibility | |
| Read | Non-invasive | Magnetic | Cortex | Established | Research frontier | |
| Read | Non-invasive | Optical | Cortex | Human feasibility | Research frontier | |
| Read | Non-invasive | Electrical | Muscle / neuromotor | Established | Established | |
| Read | Minimally invasive | Electrical | Cortex | Human feasibility | Human feasibility | |
| Read | Minimally invasive | Acoustic | Cortex, Deep brain | Early human | Preclinical | |
| Read | Invasive | Electrical | Peripheral nerve, Muscle / neuromotor | Early human | Early human | |
| Read | Invasive | Electrical | Cortex | Established | Human feasibility | |
| Read | Invasive | Electrical | Cortex | Human feasibility | Human feasibility | |
| Read | Invasive | Electrical | Deep brain, Cortex | Established | Early human | |
| Write | Non-invasive | Magnetic | Cortex | Established | Research frontier | |
| Write | Non-invasive | Electrical | Cortex | Human feasibility | Research frontier | |
| Write | Non-invasive | Acoustic | Cortex, Deep brain | Early human | Research frontier | |
| Write | Invasive | Electrical | Peripheral nerve | Established | Early human | |
| Write | Invasive | Electrical | Retina | Human feasibility | Human feasibility | |
| Write | Invasive | Electrical | Cochlea | Established | Established | |
| Write | Invasive | Electrical | Brainstem | Established | Established | |
| Write | Invasive | Electrical | Cortex | Established | Early human | |
| Write | Invasive | Electrical | Cortex | Early human | Early human | |
| Write | Invasive | Optical, Molecular | Cortex, Deep brain, Retina | Early human | Preclinical | |
| Write | Invasive | Electrical | Deep brain | Established | Early human | |
| Bidirectional | Invasive | Electrical | Peripheral nerve, Muscle / neuromotor | Early human | Early human | |
| Bidirectional | Invasive | Electrical | Cortex | Established | Early human | |
| Bidirectional | Invasive | Electrical | Cortex, Deep brain | Established | Human feasibility | |
| Bidirectional | Invasive | Electrical | Cortex, Spinal cord | Early human | Early human | |
| Bidirectional | Invasive | Electrical | Cortex | Early human | Early human | |
| Bidirectional | Invasive | Electrical | Deep brain, Cortex | Established | Early human | |
| Bidirectional | Invasive | Electrical | Deep brain | Established | Human feasibility | |
| Biohybrid | Ex vivo | Electrical, Biological | Cultured neural tissue | Adjacent frontier | Adjacent frontier | |
| Biohybrid | Ex vivo | Electrical, Optical, Biological | Cultured neural tissue | Adjacent frontier | Adjacent frontier | |
| Biohybrid | Ex vivo | Biological, Electrical | Cultured neural tissue | Adjacent frontier | Adjacent frontier | |
| Biohybrid | Ex vivo | Biological, Electrical | Cultured neural tissue | Adjacent frontier | Adjacent frontier |
Use-case explorer
Start from what people want to do
Nine human goals. Each one connects the technology, the companies, the research, the studies and the tools behind it, and says plainly what is available today.
Decoding attempted speech or writing into text and voice.
Can someone who cannot speak hold a conversation again?
Research participants with paralysis have used implanted BCIs to produce text and synthesised voice from attempted speech. All such systems remain in early feasibility studies.
Latest milestoneA single surface implant decoded speech and upper-body gestures at the same time in three participants.
- Companies
- NeuralinkSynchronPrecision NeuroscienceParadromicsBlackrock NeurotechBrainGateStairMedNeuroXessNeuCyber NeuroTechABILITY NeurotechJiMEDg.tec medical engineeringArayaCognixion
- Research
- Simultaneous speech and gesture decoding for multimodal communication in paralysisAn Accurate and Rapidly Calibrating Speech NeuroprosthesisAn instantaneous voice-synthesis neuroprosthesisA high-performance speech neuroprosthesisA high-performance neuroprosthesis for speech decoding and avatar control+10 more
- Clinical
- VOICEConnect-OneBrainGate2BRAVOUNPCortiCom+3 more
- On the calendar
- BCI Meeting 2027
Why do such different devices exist for the same goal? Each trades signal quality against surgical access. Read the dossier