# Transcranial focused ultrasound stimulation enhances semantic memory by modulating brain morphology, neurochemistry and neural dynamics

## TL;DR

Targeted ultrasound stimulation of the brain's anterior temporal lobe improves semantic memory by changing brain chemistry, activity, and structure.

## Contribution

This study demonstrates that theta-burst transcranial ultrasound stimulation enhances semantic memory through multimodal neuroimaging evidence.

## Key findings

- tbTUS improved semantic task performance compared to control stimulation.
- MRS showed decreased GABA and increased Glx, indicating changes in excitation-inhibition balance.
- VBM revealed increased grey matter volume in the anterior temporal lobe.

## Abstract

The ventromedial anterior temporal lobe (ATL) is a core transmodal hub for semantic memory, yet non-invasive modulation of this region has remained challenging. Transcranial ultrasound stimulation (TUS) offers high spatial precision suitable for deep brain targets. In this study, we investigated whether theta-burst TUS (tbTUS) to the ventromedial ATL enhances semantic memory, using a multimodal neuroimaging approach—magnetic resonance spectroscopy (MRS), functional MRI (fMRI), and voxel-based morphometry (VBM). Compared to control stimulation, tbTUS improved semantic task performance. MRS showed decreased GABA and increased Glx, reflecting shifts in excitation-inhibition balance, alongside increases in NAA, creatine and choline, suggesting enhanced neuronal metabolism. fMRI demonstrated reduced ATL activity during semantic processing and strengthened effective connectivity across the semantic network. VBM revealed increased ATL grey matter volume. These findings provide convergent evidence that tbTUS modulates neurochemistry, functional dynamics, and brain morphology to enhance semantic memory, highlighting its neurorehabilitation potential.

Jung et al. showed that targeted transcranial ultrasound stimulation of the anterior temporal lobe enhances semantic memory by altering brain chemistry, activity, and structure, highlighting a promising non-invasive approach for neurorehabilitation.