Crossed entorhino-dentate projections form and terminate with correct layer-specificity in organotypic slice cultures of the mouse hippocampus

  • The entorhino-dentate projection, i.e., the perforant pathway, terminates in a highly ordered and laminated fashion in the rodent dentate gyrus (DG): fibers arising from the medial entorhinal cortex (MEC) terminate in the middle molecular layer, whereas fibers arising from the lateral entorhinal cortex (LEC) terminate in the outer molecular layer of the DG. In rats and rabbits, a crossed entorhino-dentate projection exists, which originates from the entorhinal cortex (EC) and terminates in the contralateral DG. In contrast, in mice, such a crossed projection is reportedly absent. Using single and double mouse organotypic entorhino-hippocampal slice cultures, we studied the ipsi- and crossed entorhino-dentate projections. Viral tracing revealed that entorhino-dentate projections terminate with a high degree of lamina-specificity in single as well as in double cultures. Furthermore, in double cultures, entorhinal axons arising from one slice freely intermingled with entorhinal axons originating from the other slice. In single as well as in double cultures, entorhinal axons exhibited a correct topographical projection to the DG: medial entorhinal axons terminated in the middle and lateral entorhinal axons terminated in the outer molecular layer. Finally, entorhinal neurons were virally transduced with Channelrhodopsin2-YFP and stimulated with light, revealing functional connections between the EC and dentate granule cells. We conclude from our findings that entorhino-dentate projections form bilaterally in the mouse hippocampus in vitro and that the mouse DG provides a permissive environment for crossed entorhinal fibers.

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Author:Lars Hildebrandt-Einfeldt, Kenrick Yap, Mandy H. Paul, Carolin Stoffer, Nadine Zahn, Alexander Drakew, Maximilian Lenz, Andreas Vlachos, Thomas Deller
Parent Title (English):Frontiers in neuroanatomy
Publisher:Frontiers Research Foundation
Place of publication:Lausanne
Document Type:Article
Date of Publication (online):2021/02/11
Date of first Publication:2021/02/11
Publishing Institution:Universit├Ątsbibliothek Johann Christian Senckenberg
Release Date:2021/07/21
Tag:calretinin; dentate gyrus; layer-specificity; perforant path transection; species differences; viral tracing
Issue:art. 637036
Page Number:12
First Page:1
Last Page:12
Institutes:Medizin / Medizin
Dewey Decimal Classification:6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
Licence (German):License LogoCreative Commons - Namensnennung 4.0