Tiny Ultrasound Device Stimulates Mouse’s Brain

Using a lightweight capacitive micromachined ultrasonic transducer, researchers in South Korea were able to noninvasively stimulate the mouse brain to a depth of three to four millimeters.

AsianScientist (Mar. 28, 2019) – A research group in South Korea has devised a lightweight capacitive micromachined ultrasonic transducer (CMUT) which can be used for ultrasound brain stimulation of a freely-moving mouse. They reported their results in the journal Brain Stimulation.

Conventional methods for stimulating a specific brain region, such as deep brain stimulation (DBS) and optogenetics technology, are highly invasive because they require the insertion of probes into the brain, which makes them difficult to use for clinical application. While transcranial magnetic stimulation and transcranial electrical stimulation are noninvasive, they have a wide range and low depth of stimulation, thereby limiting target-specific treatment.

Recently, noninvasive and focused ultrasound stimulation technology has emerged as a next-generation brain stimulation alternative. Since it is delivered noninvasively, it can be applied safely in humans as well as animal experiments. Additionally, focused ultrasound stimulation is more advantageous than conventional methods in terms of providing both local and deep stimulation.

In the present study, researchers led by Professor Lee Hyunjoo at the Korea Advanced Institute of Science and Technology, South Korea, invented a small ultrasound device that can provide stimulation to the brain of a freely-moving mouse. The device weighs less than one gram—around 0.05 percent of the mouse’s weight—and has the frequency, size, focal length and ultrasonic intensity for stimulating the mouse’s brain.

To evaluate the performance of the ultrasonic device, the team stimulated the motor cortex of the mouse brain and observed the movement of its forefoot. They also measured the electromyography of the trapezius muscle.

The researchers demonstrated that their ultrasonic device can deliver ultrasound to a depth of three to four millimeters in the mouse brain and stimulate an area of the mouse brain that represents 25 percent of its total size.

Based on this research, the team is investigating the effects of ultrasound on sleep by stimulating the brain of sleeping mice.

“Going beyond experimenting on anesthetized mice, we succeeded in the brain stimulation of a freely-moving mouse. We are planning to study mice with diseases, such as Parkinson’s disease, dementia, depression and epilepsy. I believe that this basic research can contribute to treating human brain-related diseases through ultrasound brain stimulation,” said Lee.

The article can be found at: Kim et al. (2018) Miniature Ultrasound Ring Array Transducers for Transcranial Ultrasound Neuromodulation of Freely-moving Small Animals.


Source: Korea Advanced Institute of Science and Technology. Photo: Korea Advanced Institute of Science and Technology.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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