Next, we tested the mice in the Object-Location Memory Task (OLT), another hippocampal dependent task (Manns and Eichenbaum, 2009). OLT tests the ability of the animal to recognize a familiar object in a novel location. Chimeric mice exhibited a substantially greater preference for objects in novel locations than their controls (58.6 ± 4.8% vs. 41.8 ± 2.3%, means ± SEM; n=7, 7.2 ± 0.1 months, p = 0.008, t-test) (Fig. 6D). Thalidomide treatment did not affect appreciably the performance of the unengrafted littermate controls on the OLT, but reduced the performance of the human glial chimeric mice to the levels of controls (n=7, 7.8 ± 0.1 months, p=0.82, t test) (Fig. 6D). Thus, thalidomide selectively abrogated the chimerization-associated performance enhancement of the human glial chimeras.
