Fig. 5.

Key prefrontal–hippocampal neurophysiological biomarkers predict memory performance. (A) PFC theta power recorded during quiet wakefulness correlated with DIs assessed during the 24 h memory test (on a different day) in Ts65Dn mice (red asterisks and correlation coefficient); i.e., large-amplitude theta oscillations predicted poor memory performance. This dependence subsided after EGCG in the six EGCG responders (green asterisks and correlation coefficient) and in one of the two nonresponders (orange). Correlation coefficients of all EGCG-treated TS mice are shown in black. Corresponding measures for WT mice (blue asterisks and correlation coefficient) obtained during baseline periods are shown for reference. In WT mice PFC theta power did not correlate with DIs. (B) PFC to HPC theta PSI that emerged during the late visits to objects correlated negatively with DIs in WT mice; i.e., animals with more consistent PFC to HPC theta communication performed better. This relationship only emerged in the five responding TS mice after EGCG (note the distinct scales for both the DIs and the PSIs between the two plots). During the 24 h test, HPC to PFC low gamma PSI correlated positively with DIs in WT mice; i.e., animals with more consistent HPC to PFC low gamma performed better. This relationship only emerged in the five responding TS mice after EGCG. *P ≤ 0.05.