Low-intensity transcranial ultrasound stimulation modulates neural activities in mice under propofol anaesthesia
Meiqi Liu, Yi Yuan, Xingran Wang, Teng Wang, Nannan Bian, Li Zhao, Guangying Cui, Wenchao Liu, Zhongfeng Ma, Xiaochun Yang, Shujuan Liang, Zhuo Liu
BMC Neuroscience 2023 · 10.1186/s12868-023-00817-0
Abstract
Background Previous studies have reported that transcranial focused ultrasound stimulation can significantly decrease the time to emergence from intraperitoneal ketamine-xylazine anaesthesia in rats. However, how transcranial focused ultrasound stimulation modulates neural activity in anaesthetized rats is unclear. Methods In this study, to answer this question, we used low-intensity transcranial ultrasound stimulation (TUS) to stimulate the brain tissue of propofol-anaesthetized mice, recorded local field potentials (LFPs) in the mouse motor cortex and electromyography (EMG) signals from the mouse neck, and analysed the emergence and recovery time, mean absolute power, relative power and entropy of local field potentials. Results We found that the time to emergence from anaesthesia in the TUS group (20.3 ± 1.7 min) was significantly less than that in the Sham group (32 ± 2.6 min). We also found that compared with the Sham group, 20 min after low-intensity TUS during recovery from anaesthesia, (1) the absolute power of local field potentials in mice was significantly reduced in the [1-4 Hz] and [13-30 Hz] frequency bands and significantly increased in the [55-100 Hz], [100-140 Hz] and [140-200 Hz] frequency bands; (2) the relative power of local field potentials in mice was enhanced at [30-45 Hz], [100-140 Hz] and [140-200 Hz] frequency bands; (3) the entropy of local field potentials ([1-200 Hz]) was increased. Conclusion These results demonstrate that low-intensity TUS can effectively modulate neural activities in both awake and anaesthetized mice and has a positive effect on recovery from propofol anaesthesia in mice.
Abstract via europepmc.
Exposures
Exposure 1: TUS group, motor cortex
Target: motor cortex — “motor cortex”
Device: Olympus / Panametrics · Olympus, USA · V301-SU ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 500 | ✓✓✓ |
| Pulse duration (ms) | 50 | ✓✓✓⚑ |
| Pulse repetition frequency (Hz) | 1 | ✓✓✓ |
| Duty cycle (%) | 5pulse duration × PRF gives 5% | ✓✓✓ |
| Sonication duration (s) | 300 | ✓✓✓⚑ |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | not reported | |
| In-situ pressure (kPa) | 510 | ✓✓✓ |
| In-situ Isppa (W/cm²) | 8.67 | ✓✓✓ |
| In-situ Ispta (W/cm²) | 0.43 | ✓✓✓ |
Stimulation duration, PRF and duty cycle were set as 50 ms, 1 Hz and 5%; the total time for each stimulation was 5 min. The TUS group was stimulated after propofol administration.
Flags from extraction
exposures[0].timing.pulse_duration_ms— Paper calls 50 ms the 'stimulation duration'; with PRF 1 Hz and duty cycle 5% it is consistent with the pulse duration, so recorded as pulse duration (burst rule resolved by arithmetic).exposures[0].unspecified_domain.pressure_kpa— Pressure 'under the skull' measured by hydrophone 'in the water tank': domain not clear, so placed in unspecified_domain. Transducer is unfocused.exposures[0].timing.sonication_duration_s— Per-pulse 'stimulation duration' 50 ms vs 5 min total stimulation time; 300 s recorded as the train length.sham_type— Sham group is never described.n_subjects— Figure 7 legend gives n = 12 for the TUS group, inconsistent with 6 per group elsewhere.