Yu Zheng

and 5 more

Micro-magnetic technology has a small size and high spatial resolution, efficiently realizing the targeted stimulation of deep nuclei inside the brain. Studying the precise magnetic stimulation of the hippocampal trisynaptic nerve loop in the brain is essential. Within this work we designed a 1×4-array micro-magnetic stimulation (μMS) device with four submillimeter sized commercial inductance. A 3 cm circular coil was utilized to determine that the 70 kHz/2 mT/1 min stimulation parameters could elevate the LTP within the CA1 region. Then, using a micromanipulator, the μMS device was shifted to the CA1, CA3, and DG areas, after successful induction of LTP using HFS with a 1-s train of pulses delivered at 100 Hz, the fEPSPs was continuously recorded for 15 min. Based on this procedure, two magnetic stimulation schemes were utilized. Scheme a (magnetic stimulation of a single region). The 70 kHz/2 mT/1 min magnetic stimulation was introduced to CA1/CA3 and DG target regions. The experimental results revealed that the LTP enhanced the most in a single CA1 area, followed by the CA3 area, and not significantly within the DG area. Scheme b (magnetic stimulation of the multiple regions). First, the CA1 region was magnetically stimulated and fEPSPs were recorded. Then, further magnetic stimulation of various areas was performed. Experimental results revealed that the increased LTP in the CA1 region was the most effective after magnetic stimulation among the three CA1/CA3/DG regions. Magnetic stimulation of multiple areas performed better than stimulation of a single region.