by University of Würzburg
The TUS technique has the potential to safely target deeper areas of the brain even at low energies. The elliptical blue area shows its area of influence in the current study, the right prefrontal cortex. This area is associated with brain regions that produce the EEG parameter of the mid-frontal theta frequency, which is central to the study and could be successfully influenced by ultrasound. Credit: Philipp Ziebell / Johannes Rodrigues / André ForsterPsychologists at the University of Würzburg have investigated the extent to which neuromodulation of the brain with ultrasound waves influences people’s behavior. The results can also be used as a basis for therapeutic purposes.When a new opportunity opens up for people, there are some who tend to take the pessimistic view: “It’s no good anyway.” They may initially accept it, but in the long term they are in a state of inner conflict. Such an attitude can be problematic, for example, if it leads to treatment discontinuation due to potentially overwhelming symptoms of inner conflict and withdrawal in cases of mental illness, so that therapeutic interventions are unable to develop their effectiveness.A new method that scientists from the Institute of Psychology at Julius-Maximilians-Universität Würzburg (JMU) are working on could provide a remedy with ultrasound waves.The results of a study conducted by Prof. Dr. Johannes Hewig’s research group show that ultrasound can significantly influence expectations in a positive direction. If a certain region of the brain is exposed to ultrasound waves for just two minutes, it can increase a 50% positive expectation to, for example, 60% or 70%, and in some cases even more.This was shown by psychological experiments with 152 people, which were carried out in cooperation with researchers from the University of Arizona, Prof. Dr. John Allen and Dr. Jay Sanguinetti. The results were recently published in the journal Brain Stimulation.A nudge in a braver direction”The whole procedure is relatively straightforward,” explains first author Philipp Ziebell. During the treatment, a small ultrasound emitter is applied to a specific point on the head between the eye and ear for two minutes. This neuromodulation can give people a “nudge in a braver direction.” Although the study only worked with a very low ultrasound setting for safety reasons, the predicted effects were seen in a remarkably large number of test subjects.For more than 10 years, research teams have been trying to track down the possible positive effects of so-called low-intensity transcranial focused ultrasound (TUS). Prof. Dr. John Allen from the University of Arizona researched this as a Humboldt Fellow with a visiting professorship in Würzburg. As of now, the first studies have been published showing that ultrasound waves can indeed help bring depressed people out of their low mood.Objective effects in a virtual mazeIn these previous studies, the test subjects mainly used questionnaires to subjectively record the extent to which they felt better as a result of the TUS treatment. “We were now able to measure objective effects,” reports Ziebell.All test subjects took part in three test units at intervals of one week: one for preparation, one with ultrasound and one with a placebo control condition (in a so-called randomized double-blind within-subjects study design).In the decisive test unit, ultrasound was first applied to the test subjects for two minutes, after which they were wired with 64 electrodes to the head. They then went to the computer for the test in a virtual maze, which was developed in extensive preliminary work by PD Dr. Johannes Rodrigues for the simultaneous measurement of electroencephalography (EEG) and behavior.In this maze, the task of the study participants was to catch sheep and avoid spider monsters. A green light signaled them that a sheep was about to appear. They then had to move toward the sheep using a joystick. A red light warned them of the spider monster. Then they had to escape the maze as fast as possible. A yellow light signaled that either a sheep or a spider monster would appear with a 50:50 chance.In this situation, it took courage to move quickly towards a possible sheep in order to catch it in time, knowing full well that a spider monster could also appear. Or they showed avoidance behavior and left the maze—at the possibility of missing a sheep.More information: Philipp Ziebell et al, Inhibition of midfrontal theta with transcranial ultrasound explains greater approach versus withdrawal behavior in humans, Brain Stimulation (2023). DOI: 10.1016/j.brs.2023.08.011Provided by University of Würzburg
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