Dissociation of function between the dorsal and the ventral hippocampus in spatial learning abilities of the rat: a within‐subject, within‐task comparison of reference and working spatial memory

Abstract

Lesions restricted to the dorsal, but not the ventral, hippocampus severely impair the formation of spatial memory. This dissociation was first demonstrated using the water maze task. The present study investigated whether the dorsal and the ventral hippocampus are involved differentially in spatial reference and spatial working memory using a four-baited/four-unbaited version of the eight-arm radial maze task. This test allows the concurrent evaluation of reference and working memory with respect to the same set of spatial cues, and thereby enables a within-subjects within-task comparison between the two forms of memory functions. Rats with N-methyl-d-aspartic acid-induced excitotoxic lesions of the dorsal hippocampus, ventral hippocampus or both were compared with sham and unoperated controls. We showed that dorsal lesions were as effective as complete lesions in severely disrupting both reference and working spatial memory, whereas rats with ventral lesions performed at a level comparable with controls. These results lend further support to the existence of a functional dissociation between the dorsal and the ventral hippocampus, with the former being preferentially involved in spatial learning.

Spatial memory, recognition memory, and the hippocampus

“…The finding that ventral hippocampal lesions impaired spatial memory appears to differ from earlier reports that the dorsal hippocampus is important for spatial memory and that ventral lesions spare performance (22,23,(27)(28)(29). Yet one recent study did report that the ventral hippocampus was important for spatial learning under training conditions similar to those in our study (30).…”

Dissociating ventral and dorsal subicular dopamine D₁ receptor involvement in instrumental learning, spontaneous motor behavior, and motivation.

“…The results also suggest that dopamine is clearly involved in motivational processes within the vSUB but not in the dSUB. These are the first experiments to suggest separate and distinct roles for D 1 receptors in two regions of the subiculum, complementing previous work showing a functional distinction between the ventral and dorsal regions of the hippocampal formation (Bannerman et al, 1999(Bannerman et al, , 2002Caine, Humby, Robbins, & Everitt, 2001;Pothuizen, Zhang, Jongen-Relo, Feldon, & Yee, 2004).…”

Basolateral amygdala projections to ventral hippocampus modulate the consolidation of footshock, but not contextual, learning in rats

“…However, previous investigations have produced conflicting evidence regarding the role of the VH in specific aspects or types of memory (see Fanselow and Dong 2010 for larger discussion). The role of the VH in spatial information/memory processing has been unclear (Ferbinteanu and McDonald 2001;Pothuizen et al 2004;Rudy and Matus-Amat 2005), likely due to differences in the specific regions of the hippocampus targeted or identified as "VH" as well as differences in techniques and behavioral paradigms. Yet it is generally agreed that the VH plays a significant role in emotional processing including fear and anxiety (Moser and Moser 1998;Ferbinteanu and McDonald 2001;Bannerman et al 2003;Pothuizen et al 2004).…”

“…The role of the VH in spatial information/memory processing has been unclear (Ferbinteanu and McDonald 2001;Pothuizen et al 2004;Rudy and Matus-Amat 2005), likely due to differences in the specific regions of the hippocampus targeted or identified as "VH" as well as differences in techniques and behavioral paradigms. Yet it is generally agreed that the VH plays a significant role in emotional processing including fear and anxiety (Moser and Moser 1998;Ferbinteanu and McDonald 2001;Bannerman et al 2003;Pothuizen et al 2004). For example, hippocampal lesions that are confined to more ventral locations that do not connect or project to the dorsal/contextual-processing regions show reduced anxiety responses as evidenced by more time spent in the open arms of an elevated plus maze (Kjelstrup et al 2002).…”

“…In rodents, the dorsal hippocampus (DH) has been strongly implicated in spatial memories (Kim and Fanselow 1992;Moser et al 1995;Barrientos et al 2002), whereas investigations into the role of the ventral hippocampus (VH) in spatial processing remain less clear. Some studies propose VH necessity for tasks involving spatial memory (Ferbinteanu and McDonald 2001;Rudy and Matus-Amat 2005), whereas others have discounted the VH as a site for spatial processing (Moser et al 1995;Pothuizen et al 2004). In contrast, the VH has been more clearly implicated in processing emotion and anxiety (Henke 1990;Kjelstrup et al 2002;Bannerman et al 2004;Maren and Holt 2004).…”