Related Experiment Video
Updated: Jun 26, 2026
Simultaneous Focused Ultrasound Neuromodulation and Fiber Photometry Recording in Free-Moving Mouse
Published on: September 6, 2024
Parameter specific modulation of neuronal firing and extracellular action potential dynamics by transcranial focused
Haorun Huang1, Charlotte Smets1, Liyi Chen1
1Exp ORL, Department of Neurosciences, The Leuven Brain Institute, KU Leuven, Belgium.
Background:
Transcranial focused ultrasound stimulation (TUS) has emerged as a promising tool for noninvasive neuromodulation. However, the specific effects of stimulation parameters on neural activity remain incompletely understood.
Objective:
This study investigates how variations in TUS pulse repetition frequency (PRF) and pulse duration (PD) influence neural activity in the rat motor cortex.
Methods:
In vivo extracellular recordings were performed in anesthetized rats using 32-channel silicon probes while TUS was applied over the motor cortex. We systematically varied PRF (25, 50, 500 and 2000 Hz) and PD (50, 100, 200, 400 and 800 μs) and quantified changes in spike rate and extracellular action potential (EAP) shape. Control experiments included sonication of the visual cortex (V1) and the electrode holding bar. Effects were analyzed using linear mixed-effects models with Bonferroni-corrected post hoc testing.
Results:
TUS caused a significant increase in spike rate at 500 Hz PRF when the PD was set at 200 μs. When PRF was set at 50 Hz, spike rate increase at 800 μs was significantly higher than at 50 μs and 100 μs. Analysis of the EAP revealed small but significant parameter-dependent changes in action potential shape. When the most effective excitatory parameters (500 Hz PRF, 800 μs PD) were combined, a larger spike rate increase was observed in the motor cortex, compared with the other tested PRF-PD combinations and a significant change in EAP shape. The same parameters applied in the control conditions caused a smaller spike rate increase in V1 but no significant effect with the bar control, and no EAP changes were detected.
Conclusion:
These findings offer direct single-unit evidence that TUS can modify spike rate and is associated with subtle shifts in EAP waveform features in a parameter-dependent and region-specific manner. Optimizing PRF and PD is essential for reproducible neuromodulation and for moving TUS toward translational applications.
