Figure 5.

Similar hippocampal network oscillations in tg and ntg mice

(A) LFP during movement for aged littermates (ntg mouse, black, case TV140; tg mouse, green, case TV139; 18 months).

(B) Distribution chart of peak theta frequencies in aged mice for two speed bins (4–6 cm/s, p = 0.3975; 6–10 cm/s, p = 0.0701) during spontaneous movement on a running disc, and during navigation in virtual reality (VR; p = 0.0808).

(C) Empirical mode decomposition of glass electrode LFP in CA1d SP during movement (aged ntg mouse, 23 months, case TV147). Theta (IMF6), slow-gamma (IMF4), mid-gamma (IMF3), and fast-gamma (IMF2) oscillations; IMF7 likely corresponds to “delta” and IMF5 to “beta.”

(D) Probability density functions (PDFs) of instantaneous frequency for the seven IMFs. Top, aged ntg mouse (23 months, case TV147). Bottom, aged tg mouse (18 months, case TV139). Note similar distributions and spectral peaks.

(E) Left, unfiltered wideband LFP from an aging tg mouse (13 months, case TV136) with IMF6 (purple, theta) and IMF3 (orange, mid-gamma). Black curve, instantaneous amplitude for IMF3; note higher amplitude near peaks of some theta cycles (asterisks). Right, co-modulogram of a 30-s movement epoch binned for IMF6 (theta) phase. Note phase amplitude coupling for mid-gamma (IMF3) around peak-to-descending theta phase. Theta frequency also modulated by phase. Black curve, sinusoidal schematic theta cycle. Color bar: green, maximum; white, minimum amplitude.

See also Figure S6.