Ultrasound Neuromodulation and Correlation Change in the Rat Somatosensory Cortex
Sandhya Ramachandran, Xiaodan Niu, Kai Yu, Bin He
2022 · 10.1101/2022.03.18.484914
Abstract
Transcranial focused ultrasound (tFUS) is a neuromodulation technique which has been the focus of increasing interest for noninvasive brain stimulation with high spatial specificity. Its ability to excite and inhibit neural circuits as well as to modulate perception and behavior has been demonstrated, however, we currently lack understanding of how tFUS modulates the ways neurons interact with each other. This understanding would help explain tFUS’s mechanism of high-level neuromodulation and allow future development of therapies for neurological disorders. In this study we investigate how tFUS modulates neural interaction and response to peripheral electrical limb stimulation through intracranial multi-electrode recordings in the rat somatosensory cortex. We deliver ultrasound in a pulsed pattern to attempt to induce frequency dependent plasticity in a manner similar to that found following electrical stimulation. We show that neural firing in response to peripheral electrical stimulation is increased after ultrasound stimulation at all frequencies, showing tFUS induced excitation in individual neurons in vivo . We demonstrate tFUS frequency dependent pairwise correlation changes between neurons, with both potentiation and depression observed at different frequencies. These results extend previous research showing tFUS to be capable of inducing synaptic depression and demonstrate its ability to modulate network dynamics as a whole.
Abstract via europepmc.
Exposures
Exposure 1: S1HL tFUS at five SRFs
Target: primary somatosensory cortex — “S1HL region of the rat brain”
Device: Blatek · Blatek Industries, Inc., USA · AT31529 ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 500 | ✓✓✓ |
| Pulse duration (ms) | 0.2 | ✓✓✓ |
| Pulse repetition frequency (Hz) | 3,000 | ✓✓✓ |
| Duty cycle (%) | 60pulse duration × PRF gives 60% | ✓✓✓⚑ |
| 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) | not reported | |
| In-situ Isppa (W/cm²) | not reported | |
| In-situ Ispta (W/cm²) | not reported |
Nested pulsing: 200 us tone bursts at PRF 3 kHz (burst duty cycle 60%) gated at a sonication repetition frequency (SRF) of 10, 50, 75, 100 or 125 Hz at 60% duty cycle (total duty cycle 36%), delivered for five minutes between peripheral electrical stimulation epochs.
Flags from extraction
exposures[0].free_field.pressure_kpa— No pressure or intensity is reported; the text only notes the paradigm did not reach 131 kPa.n_sessions_per_subject— Each animal received two ultrasound sessions and one sham session in random order; 2 counts ultrasound sessions only.auditory_control— Sham sonication to a different brain region equidistant from auditory cortex was used to account for indirect auditory effects; not a listed vocabulary term.exposures[0].timing.duty_cycle_pct— Total duty cycle 36% (burst duty cycle 60% x 60%); 0.2 ms burst times 3 kHz PRF is consistent with the 60% burst duty cycle.n_subjects— Thirty-two animals stated in words; some sessions excluded for quality.