Influence of behavioral state on the neuromodulatory effect of low-intensity transcranial ultrasound stimulation on hippocampal CA1 in mouse
Xingran Wang, Yiyao Zhang, Kaiqing Zhang, Yi Yuan
NeuroImage 2021, 241, 118441 · 10.1016/j.neuroimage.2021.118441
Abstract
In process of brain stimulation, the influence of any external stimulus depends on the features of the stimulus and the initial state of the brain. Understanding the state-dependence of brain stimulation is very important. However, it remains unclear whether neural activity induced by ultrasound stimulation is modulated by the behavioral state. We used low-intensity focused ultrasound to stimulate the hippocampal CA1 regions of mice with different behavioral states (anesthesia, awake, and running) and recorded the neural activity in the target area before and after stimulation. We found the following: (1) there were different spike firing rates and response delays computed as the time to reach peak for all behavioral states; (2) the behavioral state significantly modulates the spike firing rate linearly increased with an increase in ultrasound intensity under different behavioral states; (3) the mean power of local field potential induced by TUS significantly increased under anesthesia and awake states; (4) ultrasound stimulation enhanced phase-locking between spike and ripple oscillation under anesthesia state. These results suggest that ultrasound stimulation-induced neural activity is modulated by the behavioral state. Our study has great potential benefits for the application of ultrasound stimulation in neuroscience.
Abstract via europepmc.
Exposures
Exposure 1: TUS to hippocampal CA1 under anesthesia, awake, and running behavioral states (Experiments A-D)
Target: CA1 — “hippocampal CA1”
Device: Olympus / Panametrics · Olympus · V323-SU (focused ultrasound transducer) ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 2,250 | ✓✓✓ |
| Pulse duration (ms) | not reportedimplied by duty cycle ÷ PRF: 0.5 ms (not stated by the paper) | ⚑ |
| Pulse repetition frequency (Hz) | 1,000 | ✓✓✓ |
| Duty cycle (%) | 50 | ✓✓✓ |
| Sonication duration (s) | 0.4 | ✓✓✓ |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | measurementsingle value | |
| In-situ pressure (kPa) | not reported | ⚑ |
| In-situ Isppa (W/cm²) | not reported | |
| In-situ Ispta (W/cm²) | not reported | |
| Pressure, domain unspecified (kPa) | 150, 300, 450, 600, 750swept | ✓✓✓ |
| Isppa, domain unspecified (W/cm²) | 0.75, 3, 6.75, 12, 18.75swept | ✓✓✓ |
16 trials were averaged per animal. Ultrasound intensity was fixed at 0.45 MPa for Experiments A (single-parameter neural activity, N=27 across 3 behavioral-state groups) and C (sleep, N=3); Experiment B (N=30) swept intensity across 0.15, 0.3, 0.45, 0.6 and 0.75 MPa to relate firing rate to intensity across states; Experiment D (N=18) repeated the single-parameter stimulation in chemically deafened mice to test for auditory confounds. The interval between TUS deliveries was 10 s within each recording session.
Flags from extraction
exposures[0].timing.pulse_duration_ms— Only 'stimulation duration' (400 ms, the train length), PRF (1 kHz) and duty cycle (50%) are stated; individual pulse width within the train is not stated in words and was not computed from duty cycle/PRF.exposures[0].in_situ.pressure_kpa— The five intensity levels (0.15-0.75 MPa) were measured 'under the skull' with a needle hydrophone per the methods (in situ, via direct measurement), and are listed together as a single exposure per the instruction to record within-target parameter sweeps as lists rather than separate exposures.n_sessions_per_subject— Paper describes 16 trials averaged per experiment but does not state how many separate sessions each individual mouse underwent.