Low-intensity transcranial ultrasound stimulation modulates neurovascular coupling in mice under propofol anesthesia

Studies have reported that low-intensity transcranial ultrasound stimulation (LI-TUS) can modulate the emergence from anesthesia. Dynamic changes in neurovascular coupling during anesthesia continuously coordinate spatial cerebral blood flow. How LI-TUS modulates neurovascular coupling to alter anesthesia need to be elucidated.

Sixteen healthy BALB/c mice were divided into the transcranial ultrasound stimulation (TUS) group (n = 8) and the Sham group (n = 8). After a surgical procedure, mice were intraperitoneally injected with propofol. Mice in the TUS group were stimulated by transcranial ultrasound. Electroencephalogram, cerebrovascular images of the cortex, and electromyography were recorded. The changes of these indicators were analyzed using optical intrinsic signal imaging and electrophysiological acquisition.

We found that LI-TUS shortened the awakening time in the TUS group. Furthermore, the following changes in the TUS group were observed: (1) During the period of recovery from anesthesia, the relative change in cerebrovascular deoxyhemoglobin was decreased at TUS-10 min, TUS-15 min and TUS-20 min; (2) During the deep anesthesia phase, the relative change of mean absolute power of local field potentials was increased at [4-8 Hz], [8-13 Hz], [13-30 Hz], and [30-60 Hz] frequency bands. Furthermore, the Pearson correlation coefficients between the relative change of mean absolute power at [60-90 Hz] frequency band and the relative change in cerebrovascular deoxyhemoglobin were smaller in the TUS group.

LI-TUS shorten the time of awakening in mice under propofol anesthesia, which may due to LI-TUS energized the neural activity, increased cerebral blood flow, improved the cerebral blood oxygenation and neurovascular coupling.