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Enhancement of functional corticomuscular coupling after transcranial ultrasound stimulation in mice

Ping Xie, Yingying Hao, Xiaoling Chen, Ziqiang Jin, Shengcui Cheng, Xin Li, Lanxiang Liu, Yi Yuan, Xiaoli Li

Journal of Neural Engineering 2022 · 10.1088/1741-2552/ac5c8b

rodenthealthyinvasive electrophysiologyemg mep

Abstract

Objective. Transcranial ultrasound stimulation (TUS), a large penetration depth and high spatial resolution technology, has developed rapidly in recent years. This study aimed to explore and evaluate the neuromodulation effects of TUS on mouse motor neural circuits under different parameters. Approach. Our study used functional corticomuscular coupling (FCMC) as an index to explore the modulation mechanism for movement control under different TUS parameters (intensity [Isppa] and stimulation duration). We collected local field potential (LFP) and tail electromyographic (EMG) data under TUS in healthy mice and then introduced the time-frequency coherence method to analyze the FCMC before and after TUS in the time-frequency domain. After that, we defined the relative coherence area to quantify the coherence between LFP and EMG under TUS. Main results . The FCMC at theta, alpha, beta, and gamma bands was enhanced after TUS, and the neuromodulation efficacy mainly occurred in the lower frequency band (theta and alpha band). After TUS with different parameters, the FCMC in all selected frequency bands showed a tendency of increasing first and then decreasing. Further analysis showed that the maximum coupling value of theta band appeared from 0.2 to 0.4 s, and that the maximum coupling value in alpha and gamma band appeared from 0 to 0.2 s. Significance . The aforementioned results demonstrate that FCMC in the motor cortex could be modulated by TUS. We provide a theoretical basis for further exploring the modulation mechanism of TUS parameters and clinical application.

Abstract via europepmc.

Speciesmouse (BALB/c)
Subjects9 animals
Sessions per subjectnot reported
Randomisedyes
Blindingnot reported
Sham / controlundescribed
Auditory controlnot reported
Readout timingonline
Anaesthesiaanaesthetised
Readoutsinvasive electrophysiology, emg mep — LFP from tail motor cortex and tail EMG; time-frequency coherence (relative coherence area)
Direction of effectmixed or unclearCorticomuscular coherence between LFP and EMG increased after TUS in theta, alpha, beta and gamma bands, mainly theta and alpha within 0.4 s; effects varied with intensity and stimulation duration.
Adverse eventsnot reportedMaximum temperature rise was estimated by calculation (not measured) as about 4.8e-3 degC.

Exposures

Exposure 1: TUS of tail motor cortex, 500 kHz, Isppa and SD sweep

Target: motor cortex — “tail motor cortex”
Device: Olympus / Panametrics · Olympus · v301-su ✓

Pulse timing
Waveformpulsed
Fundamental frequency (kHz)500✓✓✓
Pulse duration (ms)not reportedimplied by duty cycle ÷ PRF: 0.5 ms (not stated by the paper)⚑
Pulse repetition frequency (Hz)1,000✓✓✓
Duty cycle (%)50✓✓✓
Sonication duration (s)0.1, 0.15, 0.2, 0.25, 0.3, 0.4swept✓✓✓⚑
Pressure and intensity, by domain
Free-field pressure (kPa)not reported
Free-field Isppa (W/cm²)not reported
Free-field Ispta (W/cm²)not reported
In-situ estimatenot reported
In-situ pressure (kPa)not reported
In-situ Isppa (W/cm²)not reported
In-situ Ispta (W/cm²)not reported
Isppa, domain unspecified (W/cm²)0.4, 0.6, 0.8, 0.95, 1.1swept✓✓✓⚑
Protocol, in the paper’s words

30 trials per condition with a 4 s inter-trial interval; PRF 1 kHz, DC 50%; Isppa varied (0.4-1.1 W/cm2) at fixed SD, and SD varied (0.1-0.3 s) at Isppa 1.1 W/cm2.

Flags from extraction

  • n_subjects — Text states nine mice, but also that six were randomly selected as a sham group and nine were used in the TUS group; counts are inconsistent.
  • exposures[0].unspecified_domain.isppa_w_cm2 — Isppa (W cm-2) given with no statement of whether water or in situ; unspecified domain.
  • exposures[0].timing.pulse_duration_ms — Tone-burst duration is only shown symbolically in a figure legend; no number in text.
  • exposures[0].timing.sonication_duration_s — SD values 0.1-0.3 s; figure 5 caption and one results sentence give SD = 0.4 s for the intensity sweep, inconsistent with the 0.1-0.3 s range.
  • sham_type — Sham group 'without TUS'; mechanism not described.