Ultrasound-induced suppression of visually-evoked potentials: experience in nonhuman primates with a clinical transcranial MRI-guided focused ultrasound system
Nathan McDannold, Costas Arvanitis, Natalia Vykhodtseva, Margaret Livingstone
Journal of Therapeutic Ultrasound 2015 · 10.1186/2050-5736-3-s1-o24
nonhuman primatehealthyeeg megother mri
Speciesrhesus macaque
Subjects1 animals
Sessions per subject7
Randomisednot reported
Blindingnot reported
Sham / controlnone
Auditory controlnot reported
Readout timingboth
Anaesthesiaanaesthetised
Readoutseeg meg, other mri — Visually-evoked potentials (VEP) via strobe light stimulation recorded transcranially over visual cortex; MR temperature imaging for targeting; MRI to confirm blood-brain barrier disruption (with Optison microbubbles) and assess tissue damage
Direction of effectno effectAcross 133 sonications at 57 targets on/around the LGN over seven sessions, visually-evoked potentials were not significantly suppressed in any case; occasional large DC shifts (possibly cortical spreading depolarization) were observed but no consistent suppression effect.
Adverse eventsnone observedNo tissue damage was evident in MRI, and the animal recovered and behaved normally after each session.
Exposures
Exposure 1: Sonication of LGN and surrounding targets
Target: lateral geniculate nucleus — “lateral geniculate nucleus (LGN) and surrounding targets”
Device: Insightec · InSightec · ExAblate Neuro ✓
| Waveform | not reported | |
|---|---|---|
| Fundamental frequency (kHz) | 650 | ✓✓✓ |
| Pulse duration (ms) | not reported | |
| Pulse repetition frequency (Hz) | not reported | |
| Duty cycle (%) | not reported | |
| Sonication duration (s) | not reported |
| 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 |
Protocol, in the paper’s words
Recordings were obtained before, during, and after sonications at different targets over a range of pulse parameters and acoustic power levels. In some cases the focal point was steered electronically to multiple targets during each sonication. In some sessions disabling portions of the array to increase the length of the focal region was tested. Over seven sessions, a total of 133 sonications at 57 different targets on and around the LGN were evaluated.
Flags from extraction
exposures[0].timing— The abstract states sonications were delivered 'over a range of pulse parameters and acoustic power levels' but no specific numeric pulse duration, PRF, duty cycle, sonication duration or acoustic pressure/intensity values are given in the text.n_subjects— Only a single animal is described ('The animal was...'); no explicit numeral is stated for the total number of subjects.