In vitro effects of ultrasound with different energies on the conduction properties of neural tissue
Po-Hsiang Tsui, Shyh-Hau Wang, Chih-Chung Huang
Ultrasonics 2005, 43, 560-565 · 10.1016/j.ultras.2004.12.003
Abstract
The effect of ultrasound at various energy levels on the conduction properties of neural tissue is explored in this in vitro study. Excised sciatic nerves from the bullfrog were used for experiments. The nerves were stimulated by 3.5 MHz continuous wave ultrasound at 1, 2, and 3 W for 5 min. The peak-to-peak amplitude of the electrically evoked compound action potential (CAP) and the conduction velocity (CV) were measured in the nerves before and during ultrasound stimulation. The CV of the nerves increased by 5-20% for ultrasound stimulations at 1-3 W. The CAP amplitude increased by 8% during stimulation with 1 W ultrasound, and progressively decreased for 2 and 3 W ultrasound. This indicates that the effect of lower energy ultrasound increases both the CV and the CAP amplitude and that the reduction in the CAP amplitude for higher energy ultrasound is associated largely with ultrasonic thermal effects.
Abstract via europepmc.
Exposures
Exposure 1: Continuous-wave ultrasound (1, 2, or 3 W acoustic power) applied to excised sciatic nerve
Target: sciatic nerve, excised nerve — “excised sciatic nerve”
Device: Olympus / Panametrics · Panametrics · A382R ✓
| Waveform | continuous | |
|---|---|---|
| Fundamental frequency (kHz) | 3,500 | ✓✓✓ |
| Pulse duration (ms) | not applicable | |
| Pulse repetition frequency (Hz) | not applicable | |
| Duty cycle (%) | 100 | ✓? |
| 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 applicable | |
| In-situ pressure (kPa) | not applicable | |
| In-situ Isppa (W/cm²) | not applicable | |
| In-situ Ispta (W/cm²) | not applicable |
The ultrasound stimulation system was switched on to expose the nerve tissue to continuous wave ultrasound radiation at 1, 2, and 3 W. For each measurement, the sciatic nerve was stimulated by ultrasound for 5 min and its CAP signal was collected once per second.
Flags from extraction
n_subjects— Text states 'five nerve samples for each of the three ultrasound energies used'; it is not stated whether these were independent samples per energy (15 total) or the same 5 nerves reused; recorded as group-size list [5,5,5].exposures[0].free_field.isppa_w_cm2— Paper reports acoustic power in W (1, 2, 3 W) rather than an intensity in W/cm2, so no value could be placed in the intensity fields without computing area-based arithmetic.