Methods · Grey Matter

Every method in Grey Matter, filterable by its attributes.

- Brain-computer interface: A brain-computer interface (BCI) records activity from the brain and turns it, in real time, into an action outside the body, such as moving a cursor, typing, speaking through a synthesiser or moving a robotic arm, and today its main use is giving back communication and control to people who are paralysed. - Calcium imaging: Calcium imaging watches neurons fire by filming a fluorescent protein that lights up when calcium enters the cell, and it is the standard way to record thousands of identified neurons at once in a living animal. - EEG: EEG (electroencephalography) records the brain's electrical activity through electrodes on the scalp, and it is the cheapest, most portable way to follow the brain in real time, used to diagnose epilepsy, stage sleep and drive simple brain-computer interfaces. - Electrocorticography: Electrocorticography (ECoG) records the brain's electrical activity from electrodes laid directly on the surface of the cortex, under the skull, and it is used mainly to find the exact origin of seizures before epilepsy surgery and, increasingly, as the signal for brain-computer interfaces that decode speech or movemen - Epilepsy surgery: Epilepsy surgery removes, destroys or disconnects the part of the brain where seizures start, and it is the treatment most likely to stop seizures altogether in a person whose focal epilepsy has resisted medication. - FMRI: fMRI (functional magnetic resonance imaging) maps brain activity across the whole head by detecting the changes in blood oxygen that follow it, and it is the method that made it possible to see, without surgery, which areas of a healthy brain work during a task. - FNIRS: fNIRS (functional near-infrared spectroscopy) measures brain activity by shining near-infrared light into the head and reading how much returns, and it is the most portable way to follow blood oxygen in the cortex, used in infants, in moving people and outside the lab. - Functional ultrasound: Functional ultrasound images brain activity by measuring how much blood flows through the smallest vessels of each spot of tissue, and it offers fMRI-like maps at much finer resolution from a device the size of a hand, provided the skull is out of the way. - MEG: MEG (magnetoencephalography) records the tiny magnetic fields that the brain's electrical currents produce outside the head, and it is used to map where and when activity happens with millisecond timing, most often to locate the source of epileptic activity before surgery. - Microwave tomography: Microwave tomography sends low-power microwaves through the head from a ring of antennas and reconstructs a map of how the tissue inside slows and absorbs them, and its main use is to tell a bleed from a clot in a suspected stroke with equipment that fits in an ambulance. - Molecular recording: Molecular recording makes each cell write a record of its own activity into molecules inside it, to be read out later, and it is a proposed way around the wiring, bandwidth and depth limits of every method that reads the brain from outside the cell. - Optogenetics: Optogenetics makes chosen neurons respond to light by giving them a light-sensitive ion channel from algae or microbes, and it is the main tool for testing what a given set of neurons does: switch them on or off with millisecond precision and watch what changes.