Regional Specific Evidence for Memory-Load Dependent Activity in the Dorsal Subiculum and the Lateral Entorhinal Cortex

Frontiers in Systems Neuroscience

Magdalena M. Sauvage¹  Shih-pi Ku²  Liv Mahnke⁴  Motoharu Yoshida⁵  Nozomu H. Nakamura⁷  Nicolas Maingret⁷ 

[1] Center for Behavioral Brain Sciences, Otto von Guericke UniversityMagdeburg, Germany;Department of Functional Architecture of Memory, Leibniz-Institute for NeurobiologyMagdeburg, Germany;Department of Physiology, Hyogo College of MedicineNishinomiya, Japan;Faculty of Natural Science, Otto von Guericke UniversityMagdeburg, Germany;German Center for Neurodegenerative Diseases (DZNE), Cognitive Neurophysiology LaboratoryMagdeburg, Germany;Medical Faculty, Department of Functional Neuroplasticity, Otto von Guericke UniversityMagdeburg, Germany;Mercator Research Group, Functional Architecture of Memory Unit, Ruhr-UniversityBochum, Germany;

关键词: subiculum;    lateral entorhinal cortex;    immediate early gene (IEG);    Arc expression;    recognition memory;    proximal;   

DOI  :  10.3389/fnsys.2017.00051

来源: DOAJ

【 摘 要 】

The subiculum and the lateral entorhinal cortex (LEC) are the main output areas of the hippocampus which contribute to spatial and non-spatial memory. The proximal part of the subiculum (bordering CA1) receives heavy projections from the perirhinal cortex and the distal part of CA1 (bordering the subiculum), both known for their ties to object recognition memory. However, the extent to which the proximal subiculum contributes to non-spatial memory is still unclear. Comparatively, the involvement of the LEC in non-spatial information processing is quite well known. However, very few studies have investigated its role within the frame of memory function. Thus, it is not known whether its contribution depends on memory load. In addition, the deep layers of the EC have been shown to be predictive of subsequent memory performance, but not its superficial layers. Hence, here we tested the extent to which the proximal part of the subiculum and the superficial and deep layers of the LEC contribute to non-spatial memory, and whether this contribution depends on the memory load of the task. To do so, we imaged brain activity at cellular resolution in these areas in rats performing a delayed nonmatch to sample task based on odors with two different memory loads (5 or 10 odors). This imaging technique is based on the detection of the RNA of the immediate-early gene Arc, which is especially tied to synaptic plasticity and behavioral demands, and is commonly used to map activity in the medial temporal lobe. We report for the first time that the proximal part of the subiculum is recruited in a memory-load dependent manner and the deep layers of the LEC engaged under high memory load conditions during the retrieval of non-spatial memory, thus shedding light on the specific networks contributing to non-spatial memory retrieval.

【 授权许可】

Unknown