Carnegie Mellon University's He Lab is focusing on noninvasive
neuroengineering solutions that not only provide diagnostic techniques, but
also innovative treatment options. Their latest research has demonstrated
that noninvasive neuromodulation via low-intensity ultrasound can have
cell-type selectivity in manipulating neurons.
Parkinson's Disease, epilepsy and insomnia are just a few of the
neurological disorders that use neuromodulation treatment techniques today.
Neuromodulation delivers controlled physical energy to the nervous system to
treat and improve patients' quality of life. Current neuromodulation
approaches, while effective, bring both drawbacks and limitations.
"Deep brain stimulation, which is highly successful, but an invasive form of
electric stimulation through implanted electrodes, is one example of how
neuromodulation is being used in a clinical setting today," explained Bin
He, professor of biomedical engineering at Carnegie Mellon University.
"Medical professionals have also used noninvasive transcranial magnetic
stimulation and transcranial current stimulation, both of which lack the
ability to specifically focus on the neuro-circuit level. My group is
interested in helping to develop a more effective and completely noninvasive
alternative."
Low-intensity transcranial focused ultrasound, or tFUS, is an emerging and
fully reversable neuromodulation technology. It is noninvasive, precise, and
it does not require surgery. During tFUS neuromodulation, pulsed mechanical
energy is transmitted through the skull, with high spatial resolution and
selectivity, at highly-targeted brain regions, which can be steered to
elicit activation or inhibition through parameter tuning.
In work recently published in Nature Communications, He's group
demonstrated, for the first time, that specific cell types can be targeted
through tFUS neuromodulation. Their study found that excitatory neurons
showed high sensitivity to ultrasound pulse repetition frequency, while
inhibitory neurons did not.
This finding is significant, because it demonstrates the first capability
for a noninvasive neuromodulation technique to modulate a selected cell
subpopulation, using a technique that can be directly translated for human
use. With the demonstrated capability of tFUS to activate excitatory or
inhibitory neurons, future applications may lead to precise targeting of
brain circuits using focused ultrasound energy, and activate or inhibit
selected sub-populations of neurons by tuning ultrasound parameters.
"As a result of our research, we obtained direct evidence that different
neuron populations unequally respond to ultrasound stimulation in the
brain," said Kai Yu, co-first author of the paper and a research scientist
in He's lab at Carnegie Mellon University. "We identified a critical
stimulation parameter that is able to tune the balance between excitatory
and inhibitory neuronal activities, and we conducted thorough control
experiments to support these valuable neuroscience findings."
The application of this research has broad implications; it's not just
limited to one disease. For many people suffering from pain, depression and
addition, He believes non-invasive tFUS neuromodulation could be used to
facilitate treatment.
"If we can localize and target areas of the brain using acoustic, ultrasound
energy, I believe we can potentially treat a myriad of neurological and
psychiatric diseases and conditions," said He. "This type of treatment
option has great potential to shift what doctors study in medical school and
go on to practice. Of course, a noninvasive, precise, reversive treatment
option also presents endless benefits for patients. My dream would be to
make everything noninvasive."
He's next goal is to further develop the tFUS neuromodulation technology
with increased spatial resolution and focality, and directly test the
applicability of tFUS to treat brain conditions in humans.
Reference:
Yu K, Niu X, Krook-Magnuson E, He B. Intrinsic functional neuron-type
selectivity of transcranial focused ultrasound neuromodulation. Nat Commun.
2021;12(1):2519. doi:
10.1038/s41467-021-22743-7