Transcranial ultrasound stimulation as a tool to causally modulate the human hippocampus
Abstract
Background: Non-invasive brain stimulation has, until recently, had limited effect on deep brain circuits critical for memory. Transcranial ultrasound stimulation (TUS) has emerged as a promising tool to address this limitation. By delivering spatially focused acoustic energy, TUS enables targeted modulation of deep brain structures such as the hippocampus. TUS therefore provides new opportunities to causally modulate activity in neural circuits important for memory. Objective: This perspective discusses how TUS provides a potential methodological advance for human memory research, examining the mechanistic basis of the technology, emerging empirical evidence, and outstanding interpretative and technical limitations. Methods: We synthesise human and animal TUS studies targeting hippocampal and other memory-relevant circuits, compare TUS with alternative brain stimulation approaches and discuss potential clinical applications for TUS in Alzheimer's disease (AD) and medial temporal lobe epilepsy (mTLE). Results: TUS provides a tool to modulate activity in deep circuits that have been inaccessible to other forms of non-invasive brain stimulation. Human TUS studies to date document changes in neurochemistry, functional connectivity, and memory-relevant behaviour. Moreover, clinical studies in AD and mTLE report memory improvement and seizure reduction, respectively. To guide future work, we outline five critical considerations: uncertain directionality of effects, individual differences in delivered acoustic dose, state-dependence of outcomes, evidence of lasting synaptic modification, and standardisation of protocols. Conclusions: TUS holds promise for studying and enhancing human memory. Realising this potential will require concurrent neuroimaging or electrophysiology to verify target engagement, and close attention to individual differences in dose and brain state, together with cross-laboratory standardisation.
Related
- Unifying transcranial focused ultrasound and transcranial magnetic stimulation effects with calcium-dependent synaptic plasticity theory
- Transcranial Random Aperiodic Stimulation Improves Working Memory Precision
- Agentic transcranial functional ultrasound imaging: @fUS
- Edge controllability is associated with treatment response to repetitive transcranial magnetic stimulation in depression.
- Fear learning–induced brain dynamics predict individual extinction memory expression following transcranial magnetic stimulation
BibTeX
@misc{mcfarland2026transcranial,
title = {{Transcranial ultrasound stimulation as a tool to causally modulate the human hippocampus}},
author = {Craig McFarland and Miriam Klein-Flugge and Helen Barron and Valentina Mancini},
howpublished = {PsyArXiv},
year = {2026},
month = sep,
doi = {10.31234/osf.io/d7uqw_v1},
url = {https://osf.io/preprints/psyarxiv/d7uqw_v1/},
note = {CC0},
}
RIS
TY - UNPB
TI - Transcranial ultrasound stimulation as a tool to causally modulate the human hippocampus
AU - Craig McFarland
AU - Miriam Klein-Flugge
AU - Helen Barron
AU - Valentina Mancini
PY - 2026
DA - 2026/09/17
PB - PsyArXiv
DO - 10.31234/osf.io/d7uqw_v1
UR - https://osf.io/preprints/psyarxiv/d7uqw_v1/
AB - Background: Non-invasive brain stimulation has, until recently, had limited effect on deep brain circuits critical for memory. Transcranial ultrasound stimulation (TUS) has emerged as a promising tool to address this limitation. By delivering spatially focused acoustic energy, TUS enables targeted modulation of deep brain structures such as the hippocampus. TUS therefore provides new opportunities to causally modulate activity in neural circuits important for memory. Objective: This perspective discusses how TUS provides a potential methodological advance for human memory research, examining the mechanistic basis of the technology, emerging empirical evidence, and outstanding interpretative and technical limitations. Methods: We synthesise human and animal TUS studies targeting hippocampal and other memory-relevant circuits, compare TUS with alternative brain stimulation approaches and discuss potential clinical applications for TUS in Alzheimer's disease (AD) and medial temporal lobe epilepsy (mTLE). Results: TUS provides a tool to modulate activity in deep circuits that have been inaccessible to other forms of non-invasive brain stimulation. Human TUS studies to date document changes in neurochemistry, functional connectivity, and memory-relevant behaviour. Moreover, clinical studies in AD and mTLE report memory improvement and seizure reduction, respectively. To guide future work, we outline five critical considerations: uncertain directionality of effects, individual differences in delivered acoustic dose, state-dependence of outcomes, evidence of lasting synaptic modification, and standardisation of protocols. Conclusions: TUS holds promise for studying and enhancing human memory. Realising this potential will require concurrent neuroimaging or electrophysiology to verify target engagement, and close attention to individual differences in dose and brain state, together with cross-laboratory standardisation.
ER -