What is Intracortical Recording?

Neural recording performed by electrodes implanted directly within brain tissue, enabling detection of individual neuron action potentials.

What category does Intracortical Recording belong to in BCI?

Intracortical Recording is a Recording Modalities concept in brain-computer interface science.

Intracortical Recording — BCI Glossary

Intracortical recording refers to neural signal acquisition achieved by inserting microelectrodes directly into cortical tissue. This is the highest-resolution approach in the BCI field, capable of recording the electrical activity of individual neurons (single-unit activity) or small groups of neurons (multi-unit activity) at millisecond temporal resolution.

Signal Types Captured

Intracortical electrodes capture two primary classes of signals:

Action potentials (spikes): The all-or-nothing electrical discharges of individual neurons. These occur at 1-10 kHz and are the highest-information-content signal available in neural recording. Spike sorting algorithms separate overlapping spikes from different neurons recorded on the same electrode.
Local field potentials (LFPs): Slower (<300 Hz) oscillations reflecting the aggregate synaptic input to a local neural population. LFPs provide population-level information and are more stable over time than single-unit recordings.

Clinical Context

The dominant intracortical BCI platforms in human use are:

Blackrock Utah Array: 96-electrode silicon array; basis of BrainGate studies. External percutaneous connector.
Neuralink N1: 1,024-electrode flexible polymer thread array; fully wireless, inductively charged, implanted by surgical robot.

Intracortical recording provides the signal resolution needed for high-performance BCI tasks (e.g., 62 WPM typing, robotic arm control). The tradeoff is surgical invasiveness and the foreign body response — brain tissue gradually forms a glial scar around electrodes, which can degrade signal quality over months to years.

Electrode Materials and Biocompatibility

Key electrode materials include:

Silicon: Utah Array shanks; rigid, well-characterized, but mismatch in mechanical stiffness with soft brain tissue accelerates foreign body response.
Polymer/flexible: Neuralink's polymer threads; lower stiffness modulus closer to brain tissue, intended to reduce mechanical trauma and improve chronic stability.
Iridium oxide (IrOx): Common electrode tip coating for improved charge injection capacity (stimulation) and lower impedance (recording).