Figure 4
Re inactivation disrupts mPFC-dHPC theta synchrony specifically during VTEs. (A) Maze schematic demonstrating that LFP data was extracted from the choice point (blue box surrounding T-junction). Middle panel demonstrates raw LFP. Right panel shows filtered LFP as a conceptual demonstration of theta phase coherence. (B) “Theta” was defined as a 5–10 Hz oscillation based on the power spectra from mPFC and HPC LFP. (C) Frequency × Coherence plots demonstrating a clear reduction in theta coherence on VTEs (left panel) but not non-VTEs (right panel) after Re inactivation. Red colors indicate data from the muscimol testing session, while gray colors indicate data obtained across control sessions. (D) Normalized theta coherence was averaged across the 5–10 Hz range, then statistically compared between control sessions and the muscimol testing session (N = rats). There was a significant reduction in mPFC-dHPC theta coherence during VTE (left panel) but not non-VTE (right panel) trials (paired t-tests, significance threshold of 0.025 for two tests). (E) There was no significant difference in time spent at the choice point during VTEs, although the p-value was “trending”. (F) Pearson’s correlation was performed between time spent at the choice point and mPFC-dHPC theta coherence. Three separate analyses were performed to isolate control (gray) and muscimol testing (red) datasets (N = 7 rats per group), and then to combine these data (black). Regression lines are color coordinated accordingly. If reductions in mPFC-dHPC theta coherence (D) were being driven by increased time spent at the choice point (E), then we should observe negative correlations between time spent and theta coherence. Bar graphs and shaded error bars are represented as the mean ± s.e.m. *p < 0.025.
