Yet, some results do not support the hypothesis that theta-modulated slow gamma is involved in memory retrieval. Trimper and colleagues reported that ~30–50 Hz gamma coherence between CA3 and CA1 was increased in rats exploring novel objects [23], a behavior during which memory encoding, not memory retrieval, would be expected to occur. Moreover, the observed increases in slow gamma coherence were greater for objects that were subsequently remembered well compared to objects that were remembered poorly. However, in this study, rats experienced many trials containing novel objects in the same set of locations. This led Trimper et al. to speculate that the slow gamma coherence reflected recollection that different objects had been previously presented in those locations. Still, another study showed that slow gamma power in CA1 was greater on a novel W-maze compared to a familiar W-maze [17]. Again though, it is possible that rats retrieved their memory of the general W-maze paradigm in the new maze, considering that novel maze exploration was immediately preceded by a session in the familiar maze. Whatever the case may be, these results
