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
ReadInvasiveElectrical
Electrocorticography
Electrode grids rest on the surface of the brain, above or below the dura, without penetrating tissue. Thin-film micro-ECoG raises density to a thousand or more contacts.
Showing Electrocorticography: Read, Invasive.
- Where it acts
- On the cortical surface
- Information flow
- Cortex → surface grid
How far it has come
- As a clinical modality
- EstablishedRoutine in epilepsy surgery for mapping and monitoring.
- As a BCI application
- Human feasibilityResearch implants in several countries. One epidural system is authorised in China for assisted grasp.
- Access
- Invasive. A conventional grid under the dura needs a craniotomy. Implants that sit on the dura in a skull opening the size of the device, and films passed through a slit, avoid one: those systems are classed as minimally invasive in the company profiles.
- Mechanism
- Electrical
- Target
- Cortex
- Signal
- Local field potentials, including high-gamma activity
Characteristics · read interfaces
- Spatial resolutionMillimetre to sub-millimetre
- Temporal resolutionMilliseconds
- Signal richnessPopulation activity, including high gamma
- CoverageSeveral cm² per array
- InvasivenessCraniotomy; slit delivery for thin films
- Long-term stabilityStable over months to years in studies
Each track runs from low to high. A wide bar means the characteristic varies across implementations.
Strengths
- Stable signals that support long recalibration-free use
- Broad coverage of speech and motor areas
- Does not penetrate cortex
Trade-offs
- Cannot isolate single neurons
- Still requires opening the skull in most designs
Common applications
- Speech and communication
- Computer and device control
- Mapping function before and during epilepsy and tumour surgery
Human evidence
Speech decoded at a median 78 words per minute from a surface grid in one participant (2023), and a 128-channel implant that kept its control across days without recalibration (2021). A 32-participant trial supported the registration of an epidural system in China; its results are unpublished.
What needs to happen next
Fully implanted wireless systems with high channel counts, and trials large enough to support wider authorisation.
- Same site, other direction
- Used by
- Precision NeuroscienceCorTecONWARD MedicalINBRAIN NeuroelectronicsMotif NeurotechClinatecNeuracleNeuroXessNeuCyber NeuroTechABILITY NeurotechFUTRUE NeurosciencesNeurosoft BioelectronicsJiMEDGbraing.tec medical engineeringCoherence Neuro
- Research
- Simultaneous speech and gesture decoding for multimodal communication in paralysisA high-performance neuroprosthesis for speech decoding and avatar controlWalking naturally after spinal cord injury using a brain–spine interfaceMinimally invasive implantation of scalable high-density cortical microelectrode arrays for multimodal neural decoding and stimulation+8 more
- Clinical
- BRAVOBrain computer interface: neuroprosthetic control of a motorized exoskeletonUNPCortiComMRPICSINTENSE-BCI+4 more
- Datasets
- Podcast ECoGAJILE12
- Use cases
- CommunicateControlMoveRestore
- On the calendar
- BCI Meeting 2027
- Patent activity
- 140 patent families name this interface, most often on electrodes and arrays, signal processing, neural decoding. 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