What brain-imaging technique measures magnetic fields produced by the brain's natural electrical activity?

What brain-imaging technique measures magnetic fields produced by the brain's natural electrical activity?

• A. Electroencephalography (EEG)
• B. Computed Tomography (CT)
• C. Magnetoencephalography (MEG)
• D. Positron Emission Tomography (PET)

Answer: (C)

Magnetoencephalography measures the magnetic fields generated by the brain’s natural electrical activity. When groups of neurons fire in synchrony, their electrical currents create tiny magnetic fields that MEG sensors can detect noninvasively. This gives excellent temporal resolution, capturing brain activity on a millisecond timescale and is especially informative for activity in the cortex. In contrast, CT provides structural images with X-rays, not neural activity; PET tracks metabolic processes with radioactive tracers and has slower temporal resolution; EEG records electrical potentials at the scalp and is highly time-accurate but more affected by skull and scalp tissues, whereas MEG measures magnetic fields that are less distorted by the skull.

Magnetoencephalography measures the magnetic fields generated by the brain’s natural electrical activity. When groups of neurons fire in synchrony, their electrical currents create tiny magnetic fields that MEG sensors can detect noninvasively. This gives excellent temporal resolution, capturing brain activity on a millisecond timescale and is especially informative for activity in the cortex. In contrast, CT provides structural images with X-rays, not neural activity; PET tracks metabolic processes with radioactive tracers and has slower temporal resolution; EEG records electrical potentials at the scalp and is highly time-accurate but more affected by skull and scalp tissues, whereas MEG measures magnetic fields that are less distorted by the skull.