Phase Synchronization Analysis of 14-Channel LFPs in the Anterior Cingulate Cortex of Rats Under Fear Condition via Equal-Time Correlation Matrix

The aim of this study was to investigate phase synchronization of 14-channel LFPs via equal-time correlation matrix under fear conditioning. 14-channel data were recorded at anterior cingulate cortex (ACC) of rats by implicated microelectrode array, including pre-training and testing. Then low-pass filtered (fc=300Hz) to obtain LFP. Temporal phase were acquired via Hilbert Transform, phase synchronization was assessed via equal-time correlation matrix Eigenvalues of matrix were estimated and normalized and principal components were calculated by lambda i/sum(lambda i) times 100%, selected as indicants of LFP phase synchronization. Results were that lambda₁ took a (67.132 plusmn 7.995 percent) percent in sum of eigenvalues was the principal component. Value of normalized lambda₁ was lower in pre-training and changes to stimulation was not formed while in testing it increased in 0.2s after a tone stimulation, indicating that fear memory had been built up and a causally relation to the increasing synchronization was set up. These results supported that memory of pre-training and testing are based on separate neural patterns, and LFPs in ACC encoded rat´s neural activity of fear condition. The effect on measuring neural activity via equal-time correlation matrix was proved.