TY - JOUR A1 - Hildebrandt-Einfeldt, Lars A1 - Yap, Kenrick A1 - Paul, Mandy H. A1 - Stoffer, Carolin A1 - Zahn, Nadine A1 - Drakew, Alexander A1 - Lenz, Maximilian A1 - Vlachos, Andreas A1 - Deller, Thomas T1 - Crossed entorhino-dentate projections form and terminate with correct layer-specificity in organotypic slice cultures of the mouse hippocampus T2 - Frontiers in neuroanatomy N2 - 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. KW - calretinin KW - viral tracing KW - perforant path transection KW - species differences KW - layer-specificity KW - dentate gyrus Y1 - 2021 UR - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/61822 UR - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-618229 SN - 1662-5129 VL - 15 IS - art. 637036 SP - 1 EP - 12 PB - Frontiers Research Foundation CY - Lausanne ER -