Objectives: The hippocampus (HP) regulates working memory capacity (WMC) in conditions of high memory load (Sannino et al., 2012). Anatomic, genetic and behavioral studies suggested that the HP is subdivided into a dorsal (dHP) and a ventral (vHP) portion. Whether these two HP subregions differently regulate WMC is not known. Purpose: Investigate functional differences between the ventral and dorsal hippocampus in regulating the limited capacity of working memory (WM). Methods: Selective excitotoxic lesions of the dHP and vHP were performed in adult CD1 male mice. We tested control and lesioned animals in the different objects/identical objects task and in a modified version of the radial maze task (Olivito et al., 2016) to study object and spatial WMC, respectively. In the radial maze task the use of the sequential strategy to lower the memory load was prevented and allowed by the introduction and removal of a confinement procedure, respectively, in two consecutive phases of the task. Results: Both dHP lesioned and vHP lesioned impaired spatial WMC; however, vHP also impaired egocentric navigation, when animals were allowed to use of the sequential strategy. The dHP, but not the vHP, impaired object WMC. Conclusions: Our study reports that activation of the HP along its septo-temporal axis is necessary for spatial WMC, consistent with its role in allocentric navigation. The selective contribution of the dHP in object WM in condition of high memory load might be to support novelty detection processes in complex stimulus arrays. This suggests that a functional differentiation exists between the dHP and the vHP in regulating object WMC, but both subregions similarly regulate spatial WMC.
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|Titolo:||Role of dorsal and ventral hippocampus in working memory load capacity.|
|Data di pubblicazione:||2017|
|Appartiene alla tipologia:||04f Poster|