Glossary
The vocabulary of neurotechnology, in plain words.
- Action potential
- The brief voltage spike by which a neuron signals. Often just called a spike.
- Local field potential
- The summed electrical activity of many neurons near an electrode.
- Spike sorting
- Working out which recorded spikes came from which neuron.
- Electrode array
- Many recording or stimulating contacts on one device.
- Brain–computer interface
- A system that turns recorded brain activity into commands for a device. Also brain–machine interface.
- Neuroprosthesis
- A device that replaces or restores a lost function of the nervous system.
- Neuromodulation
- Changing neural activity with electrical, magnetic or chemical stimulation.
- Open loop, closed loop
- Open-loop stimulation follows a fixed programme; closed-loop stimulation adjusts to what the device senses.
- DBS
- Deep brain stimulation: a lead in a deep nucleus, driven by a pulse generator under the skin.
- TMS
- Transcranial magnetic stimulation: a coil outside the head induces current in the cortex beneath it.
- tDCS
- Transcranial direct current stimulation: a weak constant current through scalp electrodes.
- EEG
- Electroencephalography: voltage recorded at the scalp.
- ECoG
- Electrocorticography: voltage recorded from the surface of the brain.
- MEG
- Magnetoencephalography: the magnetic fields produced by neural currents.
- BOLD
- Blood-oxygen-level-dependent signal, the quantity functional MRI measures.
- fNIRS
- Functional near-infrared spectroscopy: blood oxygenation measured with light through the skull.
- Optogenetics
- Making neurons respond to light by giving them light-sensitive proteins. Mainly a research method: first shown in 2002, made practical in 2005, first tried in a patient, for blindness, in 2021.
- Impedance
- The opposition an electrode presents to current; a rough measure of contact quality.
- Gliosis
- The scar-like tissue reaction around an implant.
- Decoder
- The algorithm that maps recorded activity to an intended action.
- Neural data
- Information recorded from a person’s nervous system.