Anterior Thalamic Inputs Are Required for Subiculum Spatial Coding, with Associated Consequences for Hippocampal Spatial Memory

Just as hippocampal lesions are principally responsible for “temporal lobe” amnesia, affecting the anterior thalamic nuclei seem a similar loss of memory, “diencephalic” amnesia. Compared with former, causes diencephalic amnesia have remained elusive. A potential clue comes from how two sites interconnected, within formation, only subiculum has direct, reciprocal connections nuclei. We found that both permanent and reversible in male rats cause cessation subicular spatial signaling, reduce memory performance to chance, but leave CA1 place cells largely unaffected. suggest core element stems information output regions following pathology. SIGNIFICANCE STATEMENT At present, we know little about interactions between temporal lobe systems. Here, focused on subiculum, sole formation region directly interconnected combined nuclei, electrophysiological recordings behavioral analyses. Our results were striking clear: lesions, diverse signals normally (including cells, grid head-direction cells) all disappeared. Anterior had no discernible impact fields. Thus, firing activity requires function, does successful performance. findings provide key missing part much bigger puzzle concerning why damage is so catastrophic rodents episodic humans.