Low-Intensity Focused Ultrasound Reaches Deep Region of the Brain, Shows Potential in Reducing the Perception of Pain

Inside our brain is a region called the insula, which is an intriguing target for pain modulation. Unfortunately, it lies deep in the cortex, which makes it difficult for experts to conduct spatially specific noninvasive access. In a recent study, scientists discovered they can manipulate a spot inside the brain using focused ultrasound.

What is Focused Ultrasound?

Focused ultrasound is a noninvasive therapeutic technology that uses ultrasonic energy to target tissue deep in the body without incisions or radiation. It applies the same technology in viewing a baby in the womb but delivers a narrow band of sound waves to a small area.

This therapeutic technique is a combination of two innovative technologies. The first one provides energy in treating the tissue deep in the body in a precise and non-invasive way. The second one uses magnetic resonance or ultrasound imaging to identify and target the tissue to be treated.

When high intensity is used, ultrasound can ablate tissues. At low intensity, this technique can cause gentler, transient biological effects. Focused ultrasound therapies can be done on an outpatient basis since they do not require incision and can result in minimal discomfort and only a few complications.

Soundwaves for Pain Management

At the Fralin Biomedical Research Institute at Virginia Tech, a team of researchers utilized the potential of focused ultrasound energy to change the body's reaction to painful stimuli. The result of their study is discussed in the paper "Noninvasive neuromodulation of subregions of the human insula differentially affect pain processing and heart-rate variability: a within-subjects pseudo-randomized trial."

For many years, neuroscientists have studied how non-surgical techniques, like transcranial magnetic stimulation, can be applied in treating depression and other mental issues. This study is the first to target the insula and investigate how focused ultrasound can reach deep into the brain for pain management.

Multiple studies show that the insula is a critical brain area that is responsible for experiencing pain. It is divided into anterior and posterior portions, which are assumed to code various aspects of the pain process.

The experiment, led by Wynn Legon, involves 23 healthy human participants whose hands were heated to induce pain. They were also asked to wear a device that delivered focused ultrasound waves to a spot in their brain guided by magnetic resonance imaging (MRI). After that, the participants were asked to rate their pain perception in each application.

The research team also monitored each participant's heart rate and heart rate variability. This was done to discern brain ultrasound's effect on the body's reaction to a painful stimulus.

Participants reported that they experienced an average reduction in pain of three-fourths of a point. Although it might seem like a small amount, the experts claim that it verges on being clinically meaningful once they reach a whole point. They also believe that it can make a significant difference in quality of life and in managing chronic pain with over-the-counter medicines instead of prescription opioids.