Figure 3. Whole session coherence within and across the θ frequency band (5–12 Hz) for comparison groups in Early and Late training sessions. A, Diagram of comparison groups, ventral hippocampus to medial prefrontal cortex (vHC-mPFC) and dorsal hippocampus to medial prefrontal cortex (dHC-mPFC). B, Diagram of comparison groups, ipsilateral dHC-vHC comparisons (ipsilateral) and contralateral dHC-vHC comparisons (contralateral). C, Left, Diagram of homotopic comparison groups, mPFC, dHC, and vHC to the contralateral mPFC, dHC, and vHC, respectively (LmPFC-RmPFC, LdHC-RdHC, LvHC-RvHC). Right, Bilateral electrode configuration relative to each brain region. i, Violin plots representing whole session θ coherence with individual coherence values at each frequency bin. Ai, Ventral hippocampus to medial prefrontal cortex (vHC-mPFC) and dorsal hippocampus to medial prefrontal cortex (dHC-mPFC). Bi, Ipsilateral dHC-vHC comparisons and contralateral dHC-vHC comparisons. Ci, Homotopic comparison groups, mPFC, dHC, and vHC to the contralateral mPFC, dHC, and vHC, respectively (LmPFC-RmPFC, LdHC-RdHC, LvHC-RvHC). ii, Session × Comparison group plots of θ coherence (5–12 Hz) across the frequency band. Aii, In the Early training sessions, dHC-mPFC comparisons had greater θ coherence than vHC-mPFC comparisons. θ Coherence increased from Early to Late training sessions in both vHC-mPFC and dHC-mPFC comparisons. Bii, θ Coherence increased between Early and Late sessions for both ipsilateral and contralateral comparisons, with no difference in θ coherence between each comparison within both sessions. Cii, θ Coherence between LdHC-RdHC was greatest among comparison groups in both Early and Late training sessions. In each comparison group, θ coherence increased between Early and Late training sessions. iii, Session × Comparison group × Frequency plots of coherence within the θ frequency band. All comparison groups of Aiii, Biii, Ciii exhibited a unimodal coherence distribution within the θ frequency band with a peak at 7.4 Hz. The increases in coherence among comparison groups (Aiii, Biii) between Early and Late training sessions were largely accounted for within the bounds of this unimodal peak. Aiii, In the Early training session, LdHC-RmPFC had greater coherence uniformly throughout the bandwidth with respect to vHC-mPFC coherence values. Biii, Coherence values between ipsilateral and contralateral comparisons were similar in both Early and Late training sessions. Ciii, As was observed in previous comparison groups, in both Early and Late sessions, homotopic comparison groups exhibited a unimodal coherence distribution within the θ frequency band with a peak at 7.4 Hz. However, increases in coherence were greater at higher θ frequencies among hippocampal homotopic comparisons while the prefrontal homotopic comparisons increased at lower frequencies.