An atom-based magnetic sensor the size of a sugar cube has successfully
measured human brain activity, a
milestone that could ultimately lead to advancing our understanding of a wide
range of neurological conditions and diseases, according to researchers at the
National Institute of Standards and Technology (NIST).
We first reported on an earlier interaction of the sensor,
which has been in development since 2004, back when the team was first
able to use the sensor to track a human heartbeat in 2010.
This
week, the researchers report in the journal Biomedical Optics Expressthat their tiny
sensor -- which consists of a gas of 100 billion rubidium atoms and fiber optics to detect the
light signals that in turn register the strength of magnetic fields -- now uses
a new type of optical fiber that improves signal clarity.
"We're
focusing on making the sensors small, getting them close to the signal source,
and making them manufacturable and ultimately low in cost," says NIST
co-author Svenja Knappe in the institute's news release. "By making an
inexpensive system, you could have one in every hospital to test for traumatic
brain injuries and one for every football team."
The researchers hope the sensor will improve magnetoencephalography (MEG), a technique for measuring the magnetic
fields produced by electrical activity in the brain. Applications include
testing for traumatic brain injury, screening for visual perception in
newborns, and mapping neurological activity before surgeries that, say, aim to
treat epilepsy or remove tumors.
The current gold standard MEG is called a superconducting
quantum interference device(SQUID),
but it works best at just above absolute zero and thus requires heavy
helmet-shaped flasks with cryogenic coolants. NIST's sensor, for one, might
allow for lighter, cheaper, and less rigid helmets.
As with the tests to detect a
human heartbeat, the team worked with German scientists at a lab in Berlin that
is described as having the best magnetic shielding in the world to block the
Earth's magnetic field from interfering with extremely sensitive measurements.
(The sensor measures signals of about a trillionth of a tesla called a picotesla;
MRIs, by comparison, register closer to 1 to 8
tesla.)
The team says it anticipates being able to improve its sensor's
performance another tenfold by upping the amount of light it can detect.
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