The effect of anesthetic dose on the motor response induced by low-intensity pulsed ultrasound stimulation
Yi Yuan, Xingran Wang, Jiaqing Yan, Xiaoli Li
BMC Neuroscience 2018 · 10.1186/s12868-018-0476-2
Abstract
Background Low-intensity pulsed ultrasound stimulation (LIPUS) has been proven to be a noninvasive method with high spatial resolution and deep penetration. Previous studies have qualitatively demonstrated that the electromyographic response caused by LIPUS in the mouse motor cortex is affected by the anesthetic state of the mice. However, the quantitative relationship between motor response and anesthetic dose remains unclear. Results Experimental results show that the success rate decreases stepwise as the isoflurane concentration/mouse weight ratio increases (ratios: [0.004%/g, 0.01%/g], success rate: ~ 90%; [0.012%/g, 0.014%/g], ~ 40%; [0.016%/g, 0.018%/g], ~ 7%; 0.024%/g, 0). The latency and duration of EMG increase significantly when the ratio is more than 0.016%/g. Compared with that at ratios from 0.004 to 0.016%/g, normalized EMG amplitude decreases significantly at ratios of 0.018%/g and 0.020%/g. Conclusions Quantitative calculations indicate that the anesthetic dose has a significant regulatory effect on the motor response of mice during LIPUS. Our results have guiding significance for the selection of the anesthetic dose for LIPUS in mouse motor cortex experiments.
Abstract via europepmc.
Exposures
Exposure 1: LIPUS to mouse motor cortex across 11 isoflurane doses
Target: motor cortex — “mouse motor cortex”
Device: Olympus / Panametrics · Olympus · V301-SU ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 500 | ✓✓✓ |
| Pulse duration (ms) | 0.3 | ✓✓✓ |
| Pulse repetition frequency (Hz) | 1,000 | ✓✓✓ |
| Duty cycle (%) | not reportedpulse duration × PRF gives 30% | ⚑ |
| Sonication duration (s) | 0.2 | ✓✓✓⚑ |
| 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) | not reported | |
| In-situ Isppa (W/cm²) | not reported | |
| In-situ Ispta (W/cm²) | not reported | |
| Isppa, domain unspecified (W/cm²) | 2 | ✓✓✓ |
The PRF, SD (stimulation duration) and TBD (tone-burst duration) of the ultrasound were 1 kHz, 200 ms and 0.3 ms, respectively. Mice were anesthetized with one isoflurane concentration for 10 min before LIPUS, then LIPUS was performed for 5 min while tail EMG was recorded, followed by 5 more minutes of anesthesia; each mouse was then tested with the next of 11 isoflurane doses (0.1% to 0.6% in 0.05% steps, corresponding to ratios of 0.004%/g to 0.024%/g of body weight).
Flags from extraction
exposures[0].timing.sonication_duration_s— Paper labels this value 'SD' (stimulation duration) rather than a named sonication/train duration; a later thermal-safety calculation independently uses 'pulse duration t=0.2 s', consistent with this value being the length of one uninterrupted train.exposures[0].timing.duty_cycle_pct— Not stated by the paper; arithmetic from TBD (0.3 ms) and PRF (1 kHz) would imply ~30%, but this was not computed here per instructions.exposures[0].unspecified_domain— Paper does not state whether the reported Isppa (~2 W/cm2) is a free-field or in-situ value; placed in unspecified_domain.n_sessions_per_subject— Each of the 11 mice appears to have been tested at all 11 isoflurane doses (matching N=11 at every ratio), but the paper does not explicitly state the number of sessions per subject or whether doses were tested on separate days.