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Ultrasonic thalamic stimulation modulates neural activity of thalamus and motor cortex in the mouse

Xingran Wang, Jiaqing Yan, Huiran Zhang, Yi Yuan

Journal of Neural Engineering 2021 · 10.1088/1741-2552/ac409f

rodenthealthyinvasive electrophysiology

Abstract

Transcranial focused ultrasound stimulation (tFUS) regulates neural activity in different brain regions in humans and animals. However, the role of ultrasound stimulation in modulating neural activity and promoting neurorehabilitation in the ischemic brain is largely unknown. In the present study, we explored the effect of tFUS on neurological rehabilitation and the underlying mechanism. Adult male ICR mice (n=42) underwent transient middle cerebral artery occlusion. One week after brain ischemia, low frequency (0.5 MHz) tFUS was applied to stimulate the ischemic hemisphere of mice for 7 consecutive days (10 minutes daily). Brain infarct volume, neurobehavioral tests, microglia activation, IL-10 and IL-10R levels were further assessed for up to 14 days. We found that the brain infarct volume was significantly reduced in the tFUS treated mice compared to that in the non-treated mice ( p p p <0.05). We concluded that tFUS served as a unique technique to promote neurorehabilitation after brain ischemia by promoting microglia polarization and further regulating IL-10 signaling in the ischemic brain.

Abstract via europepmc.

Speciesmouse (C57BL/6)
Subjects42 animals
Sessions per subjectnot reported
Randomisedyes
Blindingnot reported
Sham / controlnone
Auditory controldeafened subjects
Readout timingboth
Anaesthesiaboth
Readoutsinvasive electrophysiology
Direction of effectexcitatoryUTS increased spike firing rate of thalamic pyramidal neurons and interneurons and of M1 pyramidal neurons, increased theta-band LFP power in both regions, and increased Granger-causal coupling of LFP between thalamus and M1, indicating direct excitation of the thalamus and indirect (downstream) excitation of M1.
Adverse eventsnot reported

Exposures

Exposure 1: Ultrasonic thalamic stimulation (UTS) of the posterior thalamic nuclear group

Target: posterior thalamic nucleus — “thalamus; posterior thalamic nuclear group
Device: Olympus / Panametrics · Olympus, USA · V323-SU

Pulse timing
Waveformpulsed
Fundamental frequency (kHz)500✓✓
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✓✓
Pressure and intensity, by domain
Free-field pressure (kPa)not reported
Free-field Isppa (W/cm²)not reported
Free-field Ispta (W/cm²)not reported
In-situ estimatenot reported
In-situ pressure (kPa)not reported
In-situ Isppa (W/cm²)not reported
In-situ Ispta (W/cm²)not reported
Pressure, domain unspecified (kPa)380✓✓
Isppa, domain unspecified (W/cm²)4.81✓✓
Protocol, in the paper’s words

Ultrasound was delivered as a single 400 ms stimulation train per trial, with 16 trials per recording session and a 10 s interval between successive stimuli; the firing-rate analysis window ran from 2 s before to 8 s after each UTS trial.

Flags from extraction

  • randomisedPaper states mice were 'randomly divided into two groups' for the thalamus/M1 recording assignment, not that treatment (UTS) vs a control condition was randomised; there is no sham arm in this within-subject before/after design.
  • exposures[0].timing.pulse_duration_msOnly stimulation duration (400 ms), PRF (1 kHz) and duty cycle (50%) are stated; pulse duration is derivable (duty/PRF) but is never stated explicitly, so it is left not_reported per the no-arithmetic rule.
  • n_sessions_per_subjectMethods describe 16 trials per experiment but do not state whether this was one recording session or several; left not_reported.
  • exposures[0].unspecified_domain.pressure_kpaThe 0.38 MPa 'ultrasound intensity' value and the 4.81 W/cm2 Isppa value are not stated as free-field, in-brain/derated, or through-skull; domain is unspecified so both are recorded under unspecified_domain.