Effect of three different frequencies of micro-magnetic stimulation on the neuronal electrical activity of the hippocampal CA1 neurons in mice

Abstract

Frequency is essential in regulating neuroelectric activity using magnetic fields. Current reports focus on 100 Hz or less. Studying other relatively high magnetic stimulation frequencies is necessary to reveal the influence of magnetic stimulation frequency parameters on electrical activity.This paper examined the pyramidal neurons in the CA1 region of the hippocampus of C57 mice. A custom-built micro-magnetic stimulation (μMS) device with sub-millimeter dimensions was utilized. Three magnetic field frequencies of 15 Hz, 3 kHz, and 70 kHz were chosen at a magnetic field strength of 1 mT. Precision-targeted magnetic stimulation of CA3 area neurons upstream of CA1 by whole-cell membrane clamp method. The effects of three various magnetic stimulation frequencies on the action potential (AP), sodium channel current (I_Na), and transient outward potassium channel current (I_A) of neurons in the hippocampal CA1 area were investigated. 15 Hz inhibited the excitability of pyramidal neurons within the CA1 area; 3 kHz had a facilitating effect, while the 70 kHz magnetic stimulation had a more pronounced facilitating effect. Magnetic field stimulation at 15 Hz decreased neuronal excitability, whereas magnetic field stimulation at 3 and 70 kHz increased neuronal excitability.