[Correlation between theta-gamma neural oscillations in hippocampal CA3 area and the spatial identifying and cognitive ability in rats].

The present study was aimed to explore the correlation between θ-γ neural oscillations phase-amplitude coupling (PAC) in hippocampal CA3 area and the changes of spatial identifying and cognitive ability before and after shock avoidance training in rats. According to the results of Y-type maze shock avoidance training, the rats were divided into two groups: the fast avoidance response group and the general avoidance response group. The local field potential (LFP) of hippocampal CA3 area was recorded by wireless telemetry before and after shock avoidance training. The variation of θ oscillation (3-7 Hz) and low-γ neural oscillation (30-60 Hz) PAC in hippocampal CA3 area was analyzed by MATLAB wavelet packet extraction technique. The results showed that, compared with the general avoidance response group, the fast avoidance response group exhibited higher θ-γ neural oscillation PAC in hippocampal CA3 area before training. θ-γ oscillation PAC in hippocampal CA3 area was increased in both groups after training. It was also noticed that θ-γ neural oscillation PAC of some frequency bands in the general avoidance response group were significantly higher than those in the fast avoidance response group. The results suggest that certain intensity of training can change the spatial identifying and cognitive ability of rats, and the mechanism may involve the increase of the synchrony of θ-γ neural oscillation, i.e., the enhancement of θ-γ phase-amplitude alternating frequency coupling in hippocampal neurons.