Effect of High Frequency Repetitive Transcranial Magnetic Stimulation on Local Field Potential and Spike Time-frequency Characteristics during Working Memory in Rats / 中国康复理论与实践

ABSTRACT

Objective:To investigate the effects of high frequency repetitive transcranial magnetic stimulation (rTMS) on learning memory and neuroelectric activity in rats. Methods:Eight Wistar rats were randomly divided into control group (n = 4) and rTMS group (n = 4). rTMS group was stimulated 14 days by rTMS with the frequency of 5 Hz, and the stimulation intensity was 100% motor threshold. The control group did not accepted rTMS. Then, the 16 channel local field potentials (LFPs) and spikes were recorded from their prefrontal cortex (PFC) in each group during the working memory tasks. The time-frequency analysis based on the short-time Fourier transform was performed on the LFPs, and the spike was analyzed by the release rate method. Multitaper Spectral Coherence was used to analyze the Synchronization Degree of LFPs-spike. Results:In the working memory experiment, rTMS group needed less days than the control group to reach the task correction criterion (t = 2.51, P = 0.046). The energy intensity of the θ-band and γ-band of the LFPs was significantly higher in rTMS group than in the control group (t > 12.49, P < 0.001), θ-band and γ-band LFPs-spike were more synchronized (t > 8.82, P < 0.001), but there was no significant difference in the average rate of spike between groups (t = 1.73, P = 0.067). Conclusion:High frequency rTMS could increase the LFPs energy in working memory experiment, enhance cooperative coding process for LFPs and spike, and improve the working memory ability of the rats.