Table 4.

Characteristics of non-invasive animal studies.

References	Experimental model	Intervention	Protocol of stimulation	Ganglion target	Outcomes of interest	Results
Borsody et al. (43)	Healthy Sheep (n = 6), Dogs (n = 5)	Non-invasive magnetic stimulation	Frequency: 5, 10, 20 Hz Intensity: 0.5, 1.0, 1.5 T Pulse: 280 μs Parameter: 5 min stimulation duration with 30 min recovery	Geniculate ganglion	CBF	CBF: CBF was maximized at 120% baseline CBF at 10 Hz frequency and 1.5 T
Borsody et al. (44)	Stroke Dogs (n = 12)	Non-invasive magnetic stimulation	Frequency: 10 Hz Intensity: 1.8 T Pulse: 280 μs Parameter: 5 min stimulation duration with 30 min recovery	Geniculate ganglion	Infarct volume CBF	Infarct volume: The size of ischemic core was statistically smaller in the stimulation group in comparison to the control group (P < 0.01) that showed an enlargement of ischemic core volume over time CBF: Average CBF was decreased to ≈70% of baseline levels in the ischemic hemisphere region of interest, and perfusion stayed at those depressed levels in the control group, whereas it was returned to normal by facial nerve stimulation (P < 0.01)
Chi et al. (45)	Stroke Rats (n = 24)	Non-invasive electrical stimulation	Frequency: 2/15 Hz Intensity: 1.0 mA Pulse: N/A Parameter:30 min stimulation duration	Vagus nerve	Infarct volume Neurological score CBF	Infarct volume: ratio of hemispheric infarct was significantly lowered by EA (13.60 ± 2.20%, P < 0.05), and there was no significant difference in the NEA (35.48 ± 3.23%) Neurological score: Lower neurological scores were observed in the EA group as compared to the NEA group CBF: EA induced a constant and stable increase in the CBF to the ischemic area, with a significant difference compared with the other two groups at 20, 25, 30 min (P < 0.05).
Gulturk et al. (51)	Healthy Rabbits (n = 22)	Non-invasive electrical stimulation	Frequency: 10 Hz Intensity: 5 V Pulse: 0.5 ms Parameter: 90 continuous stimulation	Trigeminal ganglion	CBF	CBF: The maximum increase in right and left CCoBF was 15.6% and 15.1% respectively. The CCoBF values of right hemisphere group were comparable to that of the left hemisphere group.
Gürelik et al. (52)	Healthy Rabbits (n = 40)	Non-invasive electrical stimulation	Frequency: 10 Hz Intensity: 5 V Pulse: 0.5 ms Parameter: 90 continuous stimulation	Trigeminal ganglion	CBF	CBF: In experiment group, CBF increased together with the beginning of electrical stimulation. The flow values were remained high as long as the stimulation. Treatment group had 15% increase in CBF as compared to sham and difference was statistically significant.
Sanchez et al. (56)	Healthy Pigs (n = 24)	Non-invasive magnetic stimulation	Frequency: 10 Hz Intensity: 1.3 T, 1.6 T, 1.9 T Pulse: 280 μs Parameter: 2, 3.5, 5 min stimulation	Geniculate ganglion	CBF	CBF: The increase in CBF occurred throughout the brain without obvious preference for the hemisphere ipsilateral to stimulation. With stimulation powers ≥ 1.3 Tesla power and durations ≥ 2 min, CBF increased in the range of 30–90% above the pre-stimulation baseline in most stimulation trials. On average, the CBF increased by 77% over baseline.

CBF, cerebral blood flow; CCoBF, cerebral cortical blood flow; EA, electroacupuncture; MABP, mean arterial blood pressure; NEA, no electroacupuncture.