Auditory responses in cats produced by pulsed ultrasound
Kenneth R. Foster, Michael L. Wiederhold
The Journal of the Acoustical Society of America 1978 · 10.1121/1.381829
Abstract
Auditory-nerve responses and cochlear microphonics are produced in cats by pulsed 5-MHz ultrasonic energy from a transducer placed against the dura mater. The pulses must be relatively intense (approximately 30 W/cm2) to produce a response, but can be sufficiently brief (less than 70 microsecond) that the brain tissue is not observably heated. The cats apparently respond to radiation pressure transients accompanying the absorption of the ultrasound in the brain tissue. Both the amplitude and latency of the N1 neural responses to the ultrasound can be matched to those produced by relatively weak tone pips or clicks from an external source. The cochlear microphonic (CM) produced by a pulse shows a prominent ringing at 5-10 kHz in different cats; the amplitued of the N1 response exhibits broad maximum, for constant amplitude pulses, a pulse widths of 20-60 microsecond. This variation of N1 response amplitude with pulse width is similar to that of a high-pass filter with a cutoff frequency at the dominent frequency of the CM, which is tentatively identified with a ringing frequency of the skull.
Abstract via europepmc.
Exposures
Exposure 1: 5 MHz pulses against dura over temporal cortex
Target: temporal lobe — “dura over the right temporal cortex”
Device: custom-built · in-house (0.6-cm PZT disk); one experiment used Panametrics · 0.6-cm-diam 5-MHz lead zirconate titanate disk in plastic tube
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 5,000 | ✓✓✓ |
| Pulse duration (ms) | 0.01, 0.07swept | ✓✓✓⚑ |
| Pulse repetition frequency (Hz) | 10 | ✓✓✓ |
| 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 | |
| Isppa, domain unspecified (W/cm²) | 30 | ✓✓✓⚑ |
Brief 5-MHz pulses of 10-70 microseconds (about 30 W/cm2 peak) repeated at 10 per second, 200-4000 responses averaged; stimulus series bracketed by tone-pip or click comparison series. Pulse width was varied at constant amplitude.
Flags from extraction
exposures[0].unspecified_domain.isppa_w_cm2— Peak intensity of about 30 W/cm2 at the dura; domain not stated; power measured by radiation balance in one setup (about 20% error).exposures[0].timing.pulse_duration_ms— Pulse width varied between 10 and 70 microseconds across stimuli; recorded as range.exposures[0].timing.sonication_duration_s— Each stimulus is a single brief pulse; no train duration stated.exposures[0].device.family— Home-made transducer; one experiment used a Panametrics immersion transducer that was reported as inadequate.auditory_control— The study is about auditory responses; comparisons with tones and a cat with broken malleus used as tests of the route, not as a control.