Studies show that low-intensity ultrasound can alter the decision-making process in the brain

Imagine working in your office while the sun is shining outside. Thinking about what you could do instead of working is an example of "counterfactual thinking".

New research on primates has shown for the first time that counterfactual thinking is linked to a frontal part of the brain, called the anterior cingulate cortex. And scientists have proven that the process can be modified by targeting the neurons (nerve cells) of this region with the help of low intensity ultrasound.

Elsa Fouragnan from Plymouth University led the study. It was published on Monday, April 15 in Nature Neuroscience.

Counterfactual thinking is an important cognitive process by which humans and animals make decisions – not only based on what they are currently experiencing, but also by comparing their current experience with potential alternatives. In typical circumstances, if these alternatives became available in the near future, they would be adopted adaptively. For example, if the sun shone during work, it would benefit as soon as the work was done.

If the neurons of the anterior cingulate cortex do not function properly, it would not be possible to switch to alternative options, even if these alternatives are the best available. Scientists think that's what happens in certain psychiatric conditions where people are stuck in dysfunctional habits.

The study showed for the first time how low intensity ultrasound waves can be used non-invasively and with extreme precision, modulate normal brain function – affecting counterfactual thinking and the ability to switch to a better alternative .

The research, conducted on macaque monkeys, follows earlier work highlighting the safety of the non-invasive ultrasound technique and its effects on the brain.

In this study, macaques were instructed to find a treat among a variety of options. They quickly learned which one was the best, but the "best" option was not always available. Thus, they had to keep this in mind for the moment when he would become available again.

After showing that the cingulate cortex was linked to recalling the best option, researchers used low-intensity ultrasound to modulate activity in this region of the brain and see its effect on behaviors. When the neurons have been stimulated, their counterfactual thinking has been altered.

Dr. Fouragnan explained why the results were so significant and what they could mean for future treatment: "This is a really exciting study for two main reasons: first, because we have discovered that the cingulate cortex is crucial to be able to switch to better alternatives, because low intensity ultrasound can be used to reversibly alter brain activity in a very specific part of the brain, "she said.

Ultrasonography is well known as an imaging tool – during pregnancy for example – but it can also be used as a therapeutic method, particularly to safely modulate brain activity. This is possible because the mechanical vibrations caused by the ultrasonic waves can cause the generation or suppression of electrical signals in the brain, which can in turn be used to restore normal brain function.

Dr. Fouragnan continued, "Ultrasound neurostimulation is a non-invasive early-stage therapeutic technology that can improve the lives of millions of patients with mental disorders by stimulating brain tissue with millimeter precision." There are currently neuromodulation techniques available. for humans, to help people with diseases such as major depression or Parkinson's disease, but no technique has this level of accuracy while remaining non-invasive.

"We are still in the early stages and the next step is to conduct other tests on humans, but the potential is very exciting."