Figure 2.

Respiration-entrained rhythm in hippocampus and OB during immobility. A, D, Raw signals (left) and time-frequency power distributions (right) of respiration (Resp, blue line) and LFPs (black lines) in OB and DG during immobility with weak (A) and strong (D) theta oscillations (θ) in two representative animals. Notice, in both examples, prominent respiration-entrained rhythms in OB and DG LFPs, which are referred to as RR and HRR. ex, Expiration; in, inspiration. B, E, Coherence spectra between OB and DG LFPs (black), between Resp and DG LFP (blue), and between Resp and OB LFP (green). Notice high coherence at respiration frequency for all pairs. In addition, coherence between OB and DG also peaks at theta frequency. C, F, Power spectra for OB and DG LFPs (black) plotted along with respiration power (blue).