24 Apr 2025

Low-intensity focused ultrasound to the amygdala changes brain activity and reduces distress symptoms in an early human study

Neurotechnology and human augmentationMedical technology and bioelectronics
AI illustration · Illustrative scene, not a photograph of the specific device or experiment.

What was demonstrated

In a double-blind, within-subject, sham-controlled target engagement study, MRI-guided low-intensity transcranial focused ultrasound was aimed at the left amygdala during fMRI in 29 patients with mood, anxiety or trauma-related disorders and 23 healthy comparison subjects. Active stimulation reduced left amygdala BOLD signal on average compared with sham. The same patients then received 15 daily sessions over three weeks in an unblinded single-arm trial. The primary outcome, the General Distress subscale of the Mood and Anxiety Symptom Questionnaire, fell significantly (p = 0.001, Cohen's d = 0.77). The authors report no serious adverse events.

Why it matters

The paper reports that focused ultrasound changed amygdala activity compared with sham in a controlled design, and that a repeated course was well tolerated in this small study. The authors argue that the findings justify double-blind randomised controlled trials to test efficacy.

Caveats

  • The clinical outcome comes from an unblinded single-arm trial. Without a sham arm, the symptom reduction cannot be attributed to ultrasound alone.
  • The target engagement study measured brain activity on fMRI, not therapeutic benefit. The authors describe the findings as initial evidence that motivates double-blind randomised trials.
  • The sample is small. The abstract reports 29 patients and 23 healthy comparison subjects. The full text could not be read, so the enrolment figures have not been checked against the body of the paper.
  • The authors call the repeated course well tolerated, with no serious adverse events, but it lasted three weeks. Long-term safety is not established.

Technology profiles

Sources

  1. peer reviewed paper
    Low-intensity transcranial focused ultrasound amygdala neuromodulation: a double-blind sham-controlled target engagement study and unblinded single-arm clinical trial
    Bryan R. Barksdale, Lauren Enten, Annamarie DeMarco et al.. Molecular Psychiatry, 24 Apr 2025. DOI: 10.1038/s41380-025-03033-w.

Last reviewed 21 Oct 2026.