Neural Recording Overview

Neural recording is the use of neurotechnologies to measure an aspect of brain function and the electro-physiological responses of single neurons.

Common neuroimaging methods for measuring brain function include: Positron emission tomography (PET), Functional magnetic resonance imaging (fMRI), multichannel electroencephalography (EEG), magnetoencephalography (MEG), near infrared spectroscopic imaging (NIRSI), and Single-photon emission computed tomography (SPECT). Single neuron measurement normally uses a microelectrode system.

Single-unit and multi-electrode recording

Single-unit recordings provide a method of measuring the electro-physiological responses of single neurons using a microelectrode system.

When a neuron generates an action potential, the signal propagates down the neuron as a current which flows in and out of the cell through excitable membrane regions in thesoma and axon. A microelectrode is inserted into the brain, where it can record the rate of change in voltage with respect to time.

Electroencephalography

Electroencephalography (EEG) is typically a non-invasive (however invasive electrodes are often used in specific applications) method to record electrical activity of the brain along the scalp. EEG measures voltage fluctuations resulting from ionic current within the neurons of the brain.

In clinical contexts, EEG refers to the recording of the brain's spontaneous electrical activity over a period of time, as recorded from multiple electrodes placed on the scalp. Diagnostic applications generally focus on the spectral content of EEG, that is, the type of neural oscillations that can be observed in EEG signals.

Functional magnetic resonance imaging

Functional magnetic resonance imaging or functional MRI (fMRI) is a functional neuroimaging procedure usingMRI technology that measures brain activity by detecting changes associated with blood flow.

This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area of the brain is in use, blood flow to that region also increases.

Magnetoencephalography

The magnetoencephalogram (MEG) is a record of magnetic fields, measured outside the head, produced by electrical activity within the brain.

Typically MEG sensors are housed in a helmet shaped container (or dewar) in which the subject places their head during the measurement process.

Skip to toolbar