Fig. 13.

Coherence between theta oscillations in str. radiatum (r) and dentate inner molecular layer (im) after entorhinal cortex lesion. A, Changes in coherence function between inner molecular and locations 200 μm above (hippocampal fissure, hf) or below (hilar region, h). Ordinary coherence values were high in the entire 0–30 Hz band and were not affected by partialization with signals in str. oriens (prt: o). Partialization with radiatum (prt: r) selectively decreased inner molecular–hippocampal fissure and inner molecular–hilus coherence at theta frequency but did not change the wide-band coherence. Inner molecular–hippocampal fissure coherence values, on the other hand, were eliminated at all frequencies by partialization with a signal recorded from between the hippocampal fissure and the inner molecular layer in the dentate molecular layer (prt: m). Partialization with hilus signal (prt: h) decreased the wide-band component of the coherence function but had no effect on the theta coherence.B, Partialization with radiatum (prt: r, inset) selectively eliminated theta coherence between the inner molecular and all other signals.