High-resolution probe may help unlock secrets of brain function and neurological diseases
The probe records activity of neurons in the human brain with
unprecedented clarity and precision.

Date:
February 14, 2022
Source:
Massachusetts General Hospital
Summary:
A novel probe developed in 2017 allowed unprecedented recording of
brain activity but only in small lab animals. MGH researchers and
colleagues have successfully used a modified version of the probe
to measure brain activity in humans. Insights gleaned from data
acquired by this modified tool could have profound implications
for the understanding of how the brain functions in good health
and in disease.



FULL STORY ==========================================================================
How brain cells communicate with one another remains largely cloaked in mystery, but a probe that records signals from neurons with unprecedented clarity and precision may help unlock those secrets, according to
a study by researchers at Massachusetts General Hospital (MGH) and
colleagues at several other institutions. These findings, reported in
Nature Neuroscience, could lay the foundation for a better understanding
of how the brain works, the origins of neurological diseases, and more.


==========================================================================
In 2017, a digital technology company in Belgium called IMEC, in
conjunction with the Howard Hughes Medical Institute (including the
Janelia Research Campus), introduced the Neuropixels probe, a tool for recording the activity of brain cells, or neurons. "The Neuropixels device
has revolutionized the field of neuroscience," says neuroscientist and electrophysiologist Angelique Paulk, PhD, a researcher at MGH's Center
for Neurotechnology and Neurorecovery and lead author of the study.

Earlier technologies for recording the activity of neurons generally
relied on relatively large electrodes inserted into the brain. "They
can sample activity from thousands of brain cells at once, but that
produces a blurry view," says Paulk. She switches to an audio analogy to describe the quality of recordings by older devices: Imagine standing
in the middle of a packed football stadium, listening to the crowd
roar. By contrast, the Neuropixels probe is much smaller, but has far
superior resolution. "Instead, it's like you're able to record hundreds
of individual voices, each with its own microphone," says Paulk.

The original Neuropixels probe, however, was designed as a research tool
for use in small lab animals such as rodents. Neuroscientists immediately expressed interest in a tool that could be used to study human brains,
which required some modification. For instance, the original Neuropixels
probe was too fragile for use in the large human brain, so it had to be
made thicker. Still, says Paulk, the probe is only the width of about
three hairs.

The goal of the Nature Neuroscience report was to develop techniques
for using the modified Neuropixels probe to record brain activity
in human patients undergoing neurosurgery in an operating room. Nine
patients already slated to have neurosurgery to treat several different conditions consented to allow MGH neurosurgeons to record their brain
activity during the procedures.

The team, which included epilepsy specialist Sydney Cash, MD, PhD, and neurosurgeon Ziv Williams, MD, both of MGH, experienced challenges in
using the Neuropixels probe in humans, as six attempts to record brain
activity were unsuccessful. However, they were able to successfully
record brain activity in three patients, one undergoing treatment for
epilepsy, while the other two received implants that provide deep-brain stimulation for treatment of movement disorders. In one of the latter
patients, the team recorded the activity of 202 individual neurons.

Why is it important to record the behavior of individual neurons? "Thanks
to new higher-resolution tools, we're finding that different cell
types are doing very interesting things," says Paulk. For example,
excitatory neurons generate signals, while inhibitory neurons slow or stop them. Small probes already available can record the activity of one or two neurons, "but that means that you're not really capturing the diversity
of cell types," says Paulk. "Being able to sample 200 cells all at the
same time tells us how the cells talk to each other. It's that special interplay that allows our brain circuits to work." Decoding communication between neurons with the aid of the Neuropixels probe and other tools
could lead to new revelations about neurological conditions such as
epilepsy and how tumor cells invade neighboring cells in the brain, says
Paulk, as well as aid developers of tools that allow disabled people to
use their brains to operate computers and robotic devices that let them
live more independently. Ultimately, this new technology could provide invaluable insights about the very nature of cognition, such as how we
form thoughts and perceive the world around us.

Paulk is an instructor in Neurology at Harvard Medical School (HMS). Cash
is an associate professor of Neurology at HMS and directs the Cash Lab
at the MGH Center for Neurotechnology and Neurorecovery. Williams is an associate professor of Neurosurgery at HMS and directs the Williams Lab
at the Center for Nervous System Repair at HMS.

This work was supported by the Tiny Blue Dot Foundation, the National Institutes of Health, the Simons Foundation, and the Howard Hughes
Medical Institute at Stanford University.

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dreams in this free online course from New Scientist -- Sign_up_now_>>> ========================================================================== Story Source: Materials provided by Massachusetts_General_Hospital. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Angelique C. Paulk, Yoav Kfir, Arjun R. Khanna, Martina L. Mustroph,
Eric
M. Trautmann, Dan J. Soper, Sergey D. Stavisky, Marleen
Welkenhuysen, Barundeb Dutta, Krishna V. Shenoy, Leigh R. Hochberg,
R. Mark Richardson, Ziv M. Williams, Sydney S. Cash. Large-scale
neural recordings with single neuron resolution using Neuropixels
probes in human cortex. Nature Neuroscience, 2022; 25 (2): 252 DOI:
10.1038/s41593-021-00997-0 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220214154859.htm

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