Figure 3. The performance of EAE mice in the hole-board learning test is impaired but restored by the minocycline treatment.

(A) Scheme of a hole-board apparatus that includes four sectors and holes in the floor, for measuring horizontal motor activity, vertical motor activity (rearings) and nose pokes. (B–D) Histograms showing vertical motor activity as number of rears (B), horizontal locomotor activity as number of intertrial crossings (C) and hole exploration activity as number of head-dippings (D) during a 2-session holeboard test performed in control mice, remitting EAE mice and remitting EAE mice treated with minocycline. Note that vertical and horizontal activities (B,C) are not significantly different in the three experimental groups. (D) Control mice showed significantly less head-dippings when re-exposed to the hole-board compared with their initial performance. Conversely, EAE mice in the remission phase explored the holes to an equal degree after hole-board re-exposure, suggesting the presence of a learning/recognition deficit. The minocycline-treated remitting EAE mice showed a performance that was not different from that of control mice (***P < 0.001).