Strengthened functional connectivity among LFPs in rat medial prefrontal cortex during anxiety.

Theta oscillations in medial prefrontal cortex (mPFC) have been consistently implicated in the regulation of anxiety-related behaviors. However, the theta-band functional connectivity in mPFC is less well characterized. Therefore, we simultaneously recorded local filed potentials (LFPs) from mPFC in freely behaving rats in the elevated plus maze (EPM). Functional connectivity among LFPs was measured by directed transfer function (DTF) via spectral Granger causal connectivity analysis. Causal network was then identified based on DTF. Global efficiency (E) was selected to quantitatively describe the characteristic of the network. Our results showed that a significant difference in theta-band functional connectivity between safe and aversive location in the maze anxiety test. Strikingly, DTF and E were higher specifically in the closed arms and decreased sharply prior to entrying into the open arms. These results indicate strengthened theta-band functional connectivity may be related to anxiety.