Deconstructing the Direct Reciprocal Hippocampal-Anterior Thalamic Pathways for Spatial Learning

• DOI: 10.1523/jneurosci.0874-20.2020
• Publication Date: 2020-08-04T23:54:43Z
• Authors: Andrew J.D. Nelson; Lisa Kinnavane; Eman Amin; Shane M. O'Mara; John P. Aggleton
• Keywords: Subiculum; Cytoarchitecture; Anterograde amnesia

The hippocampus is essential for normal memory but does not act in isolation. anterior thalamic nuclei may represent one vital partner. Using DREADDs, the behavioral consequences of transiently disrupting function were examined, followed by inactivation dorsal subiculum. Next, anterograde transport an adeno-associated virus expressing DREADDs was paired with localized intracerebral infusions a ligand to target specific input pathways. In this way, direct projections from hippocampal formation inhibited, separate inhibition subiculum nuclei. To assay spatial working memory, all animals performed reinforced T-maze alternation task, then more challenging version that nullifies intramaze cues. Across four experiments, deficits emerged on task precluded use Inhibiting produced severest deficit. This deficit revealed key contribution anteromedial and anteroventral processing allocentric information, associated head-direction information. overall pattern results provides consistent causal evidence two-way functional significance hippocampal-anterior interactions processing. At same time, these findings are hypotheses same, reciprocal underlie common core symptoms temporal lobe diencephalic amnesia. <b>SIGNIFICANCE STATEMENT</b> It has long been conjectured might be partners that, respectively, they principally responsible However, relationship lacking. Here, we examined silencing interconnections between two brain regions tests learning. Disrupting information flow vice versa impaired performance By revealing conjoint importance pathways, help explain why pathology either medial diencephalon or lobes can result profound amnesic syndromes.