Differential contributions of dorsal vs. ventral hippocampus to auditory trace fear conditioning

Time course of dorsal and ventral hippocampal involvement in the expression of trace fear conditioning

“…These results are consistent with those from previous studies in our laboratory (Czerniawski et al, 2009;Yoon & Otto, 2007) and others (e.g. Burman et al, 2006) which strongly suggest that VH is critical to the expression of trace fear conditioning shortly after training, and extend those findings to suggest that integrity of the VH remains necessary for expression for at least 42 days after learning.…”

“…Subjects infused with saline froze robustly during the trace interval and second and third ITI, but not during the presentation of the CS or during the initial ITI. This pattern of freezing behavior of control subjects is consistent with previous data from our laboratory (Czerniawski et al, 2009;Yoon & Otto, 2007) and likely indicates that the trace interval, rather than the CS, best predicts the onset of the US during trace fear conditioning. It is also important to note that the deficit caused by inactivation diminished in a progressive-yet statistically insignificant-manor as the training-testing interval increased.…”

“…Conversely VH, but not DH, establishes direct and reciprocal connections with the amygdala (Pitkanen et al, 2000), a brain area known to play a prominent role in emotional learning and anxiety states (LeDoux, 1995). Consistent with these neuroanatomical dissociations, we have recently reported a double dissociation between VH and DH in the acquisition and expression of auditory trace fear conditioning and spatial learning, respectively (Czerniawski et al, 2009;Czerniawski et al, 2011;Yoon & Otto, 2007). Collectively, these data suggest that the dorsal and ventral hippocampal subregions may contribute differently to the acquisition and subsequent expression of a variety of mnemonic processes, and that the apparently discrepant data reviewed above may reflect functional differences between DH and VH.…”

“…First, most studies exploring the role of the hippocampus in systems consolidation have examined the effects of damage to either the majority of the hippocampal formation or selective damage to the dorsal hippocampus (DH) alone (see Sutherland et al, 2010 for review). By contrast, relatively few studies have selectively examined the contributions of the ventral hippocampus (VH) to recall in general and systems consolidation in particular (Czerniawski et al, 2009;Martin et al, 2005;Sutherland et al, 2008;Yoon & Otto, 2007). While DH and VH are extensively interconnected, these subdivisions receive notably different afferents and, moreover, the roles associated with the sources of these afferents are consistent with recent data demonstrating the dissociable roles of DH and VH in different forms of learning.…”

“…For example, we have previously found that post-training excitotoxic lesions of DH performed 24hr after trace fear conditioning dramatically impair subsequent performance during testing (Yoon & Otto, 2007), while temporary inactivation of DH prior to testing has no effect. Similar differences between the effects of lesions and temporary inactivation have been reported using other paradigms (Holt & Maren, 1999;Resstel et al, 2008).…”