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.
ABSTRACT
Objective To develop a new algorithm to reconstruct the distribution of acoustic sources of magnetoacoustic tomography with magnetic induction(MAT-MI)in the acoustic inhomogeneous media,which is developed on the basis of generalized finite element method (GFEM) and modified time inversion algorithm. Methods The acoustic and acoustic coupling theory and the basic equations of acoustics were used to study the forward and inverse problems of the acoustic inhomogeneous concentric sphere magneticacoustic coupling model. The solution of acoustic non-uniform media wave equation based on GFEM was proposed.The method solved the problem of acoustically inhomogeneous media sound source reconstruction and conductivity reconstruction.At the same time,the distribution of velocity was reconstructed by rotating the pairs of transducers and the time reversal algorithm. Results The proposed algorithm could accurately reconstruct the acoustic source distribution in acoustic inhomogeneous media,and could obtain the distribution of sound velocity during the reconstruction of sound source and recover the image well. Conclusion The proposed algorithm had its feasibility and effectiveness verified,and gains advantages in MAT-MI reconstruction of acoustic inhomogeneous media.