Fig. 1. Morphological and functional integrity of hippocampal slice cultures used as recipient tissue for ESGPs. (A) A 400 µm-thick slice one day after explantation. Dentate gyrus (DG), pyramidal-cell layer (CA3-CA1), entorhinal cortex (EC) and adjacent regions of the temporal cortex (TC) are well delineated. SC, Schaffer collaterals; MF, mossy fibers; PP, perforant path. (B) Cryostat section (10 µm) of a slice preparation maintained in culture for 31 days. Note the morphological preservation of the key anatomic structures (Hematoxylin and Eosin staining). The inset shows typical field potentials following orthodromic stimulation of the perforant path (PP-DG) and the Schaffer collaterals (SC-CA1) at the end of the culture period (stimulation artifacts blanked). (C) Anterograde tracing with rhodamine-conjugated dextran (Micro-Ruby®) confirms the integrity of the perforant path at 33 days in culture. (D) TIMM stain (performed according to Zimmer and Gähwiler, 1984) demonstrating the histological preservation of the MF system of a slice culture maintained for 33 days (20 µm cryostat section). Scale bars: 1 mm.