Transversal functional connectivity and scene-specific processing in the human entorhinal-hippocampal circuitry.

Scene and object information reach the entorhinal-hippocampal circuitry in partly segregated cortical processing streams. Converging evidence suggests that such information-specific streams organize the cortical - entorhinal interaction and the circuitry's inner communication along the transversal axis of hippocampal subiculum and CA1. Here, we leveraged ultra-high field functional imaging and advance Maass et al., 2015 who report two functional routes segregating the entorhinal cortex (EC) and the subiculum. We identify entorhinal subregions based on preferential functional connectivity with perirhinal Area 35 and 36, parahippocampal and retrosplenial cortical sources (referred to as ECArea35-based, ECArea36-based, ECPHC-based, ECRSC-based, respectively). Our data show specific scene processing in the functionally connected ECPHC-based and distal subiculum. Another route, that functionally connects the ECArea35-based and a newly identified ECRSC-based with the subiculum/CA1 border, however, shows no selectivity between object and scene conditions. Our results are consistent with transversal information-specific pathways in the human entorhinal-hippocampal circuitry, with anatomically organized convergence of cortical processing streams and a unique route for scene information. Our study thus further characterizes the functional organization of this circuitry and its information-specific role in memory function.