A miniature atom-based magnetic sensor developed by the National Institute of Standards and Technology (NIST) has passed an important research milestone by successfully measuring human brain activity.

Experiments reported this week verify the sensor's potential for biomedical applications such as studying mental processes and advancing the understanding of neurological diseases.

NIST and German scientists used the NIST sensor to measure alpha waves in the brain associated with a person opening and closing their eyes as well as signals resulting from stimulation of the hand. The measurements were verified by comparing them with signals recorded by a SQUID (superconducting quantum interference device).

SQUIDs are the world's most sensitive commercially available magnetometers and are considered the "gold standard" for such experiments. The NIST mini-sensor is slightly less sensitive now but has the potential for comparable performance while offering potential advantages in size, portability and cost.

The study results indicate the NIST mini-sensor may be useful in magnetoencephalography (MEG), a noninvasive procedure that measures the magnetic fields produced by electrical activity in the brain.

MEG is used for basic research on perceptual and cognitive processes in healthy subjects as well as screening of visual perception in newborns and mapping brain activity prior to surgery to remove tumors or treat epilepsy. MEG also might be useful in brain-computer interfaces.