Dillingham Christopher M, Erichsen Jonathan T, O'Mara Shane M, Aggleton John P, Vann Seralynne D
School of Psychology, Cardiff University, Cardiff, United Kingdom.
School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom.
Hippocampus. 2015 Sep;25(9):977-92. doi: 10.1002/hipo.22421. Epub 2015 Mar 3.
The hippocampal formation and anterior thalamic nuclei form part of an interconnected network thought to support memory. A central pathway in this mnemonic network comprises the direct projections from the hippocampal formation to the anterior thalamic nuclei, projections that, in the primate brain, originate in the subicular cortices to reach the anterior thalamic nuclei by way of the fornix. In the rat brain, additional pathways involving the internal capsule have been described, linking the dorsal subiculum to the anteromedial thalamic nucleus, as well as the postsubiculum to the anterodorsal thalamic nucleus. Confirming such pathways is essential in order to appreciate how information is transferred from the hippocampal formation to the anterior thalamus and how it may be disrupted by fornix pathology. Accordingly, in the present study, pathway tracers were injected into the anterior thalamic nuclei and the dorsal subiculum of rats with fornix lesions. Contrary to previous descriptions, projections from the subiculum to the anteromedial thalamic nucleus overwhelmingly relied on the fornix. Dorsal subiculum projections to the majority of the anteroventral nucleus also predominantly relied on the fornix, although postsubicular inputs to the lateral dorsal part of the anteroventral nucleus, as well as to the anterodorsal and laterodorsal thalamic nuclei, largely involved a nonfornical pathway, via the internal capsule.
海马结构和前丘脑核是相互连接网络的一部分，该网络被认为与记忆功能有关。这个记忆网络的一条核心通路包括从海马结构到前丘脑核的直接投射，在灵长类动物大脑中，这些投射起源于下托皮质，通过穹窿到达前丘脑核。在大鼠大脑中，已经描述了涉及内囊的其他通路，这些通路将背侧下托与丘脑前内侧核相连，以及将后下托与丘脑前背侧核相连。确认这些通路对于理解信息如何从海马结构传递到前丘脑以及它如何可能因穹窿病变而被破坏至关重要。因此，在本研究中，将通路示踪剂注射到患有穹窿损伤的大鼠的前丘脑核和背侧下托中。与先前的描述相反，从下托到丘脑前内侧核的投射绝大多数依赖于穹窿。背侧下托向大多数腹前核的投射也主要依赖于穹窿，尽管后下托对腹前核外侧背侧部分以及对丘脑前背侧核和丘脑外侧背侧核的输入在很大程度上涉及一条不经过穹窿的通路，即通过内囊。
