e., which room the animal is in) (Kjelstrup et al., 2008). Accordingly, the mPFC, whose inputs arise mostly from ventral and intermediate hippocampus, exhibits no evidence of place cell-like responses but does discriminate between rooms (Hyman et al., Small molecule library 2012; Jung et al., 1998; Poucet, 1997). Recent evidence has established that the firing of hippocampal

place cells is modulated by environmental stimuli (Leutgeb et al., 2005). Given its strong connectivity with limbic structures, ventral hippocampus may encode nonspatial contextual signals for such things as odors, bodily states, and emotions (Pennartz et al., 2011). Hence, as has been previously suggested, the hippocampal input is a plausible source of spatial and emotional context (Jung et al., 1998; Pennartz et al., 2011). The other possible role for hippocampal this website input to mPFC is to support rapid learning. Wise and Murray (2000) have provided evidence that arbitrary visual-motor mappings formed within premotor cortex initially depend on rapid associative mechanisms within the hippocampus but, through consolidation, become hippocampally independent. A similar principle may apply to the mPFC. To wit, the rapid formation and consolidation of associations between contexts, events, and responses

within mPFC may depend on hippocampus, whereas long-term storage may be mediated mostly by mPFC. The aforementioned evidence for coordinated memory replay in mPFC and hippocampus during consolidation

supports this claim. The role of communication between hippocampus and mPFC has been studied via functional disconnection, in which the mPFC is inactivated in one hemisphere and the hippocampus is inactivated in the other. Because the connections between hippocampus and mPFC are unilateral, the animal is left with one intact hippocampus and one intact mPFC but no pathway between them (Floresco et al., 1997). This technique Ketanserin has been used to demonstrate that mPFC-hippocampal communication is necessary for short-term memory in paradigms including the water maze (Wang and Cai, 2008), the T maze (Wang and Cai, 2006), spatial win-shift on the radial arm maze (Floresco et al., 1997; Goto and Grace, 2008), and the Hebb-Williams maze, a spatial maze requiring a specific set of turns to reach reward (Churchwell et al., 2010). In fact, the effects of mPFC-hippocampal disconnection are nearly the same as those seen after bilateral mPFC inactivation, supporting the claim that mPFC is dependent upon the hippocampal-mPFC pathway either for context or for rapid learning. As further evidence for a functional interaction between mPFC and hippocampus, electrophysiological rhythms in these two structures are coupled, particularly in the theta range. Roughly half of mPFC cells exhibit phase locking to hippocampal theta while rats engage in spatial tasks (Hyman et al., 2005; Siapas et al., 2005).