Researchers at the University of Oxford collaborated with former Foundation Scholar Jean-Francois Aubry’s team in Paris to study whether low-intensity focused ultrasound could be used to reversibly modulate brain activity for a long time period with high spatial specificity. In two preclinical studies, the collaborative team was successful at first developing a protocol that modulated brain activity for more than an hour and then testing the protocol in several regions of the brain.
Offline Impact of Transcranial Focused Ultrasound on Cortical Activation in Primates
In this first study, the research teams developed a 40-second stimulation protocol that successfully achieved the following: (1) modulated brain activation in macaques for more than one hour, (2) caused stimulated areas to interact more selectively with the rest of the brain, (3) created regionally specific effects in both the supplementary motor area and the frontal polar cortex of the medial frontal lobe, and (4) induced signal changes in the meningeal compartment. The temporary effects did not appear to cause microstructural changes. See eLife >
Manipulation of Subcortical and Deep Cortical Activity in the Primate Brain Using Transcranial Focused Ultrasound Stimulation
To determine whether the transcranial ultrasound protocol could reach a subcortical brain structure and a deep cortical region, the researchers then sought to establish a causal role between stimulating a neural network to interfere with its activity while measuring the impact of the stimulation. They chose to target the amygdala and the anterior cingulate cortex while measuring neurological changes during functional magnetic resonance imaging (fMRI). The control activity in each area was specifically reduced after sonication. Dissociable and focal effects on neural activity could not be explained by auditory confounds. See Neuron >
The eLife journal summarized the work in a story titled "Brain Stimulation Goes Ultrasonic". A lively Twitter thread included comments such as, “If this holds up, it would be massive” and “Awesome thread on new non-invasive ultrasound stimulation.”
Anatomical and Technical Reappraisal of the Pallidothalamic Tractotomy with the Incisionless Transcranial MR-Guided Focused Ultrasound. A Technical Note
Researchers in Switzerland have published the first article in a recent series wherein they report using focused ultrasound to perform pallidothalamic tractotomy lesioning for patients with Parkinson’s disease. The team seeks to further define their process – which helps handle individual anatomic variability and prevents the recurrence of symptoms – to share their approach with other practitioners. Their technique also employs rapid, multiple small thermal lesions that are distributed in a preplanned manner to optimize target coverage. The group works in partnership with a company called SoniModul, which offers public data on treatment results and complications. The next two articles in the series will address radiological and clinical results. See Frontiers in Surgery >