The performance of two experimental groups--one with lesions of the perforant paths projecting to the dorsal hippocampus (the D group) and one with lesions of the perforant paths to both the dorsal and ventral hippocampus (the DV group)--was compared with the performance of a lesioned control group and an intact control group during two test sessions in the Hebb-Williams maze. Both experimental groups displayed impaired maze learning in Session I. The DV group showed some recovery of function in Session II, and the D group was indistinguishable from controls. The results are discussed in terms of reduced sensory information to the hippocampal formation resulting from perforant paths lesions. It is suggested that the hippocampus is involved in relating new stimuli to previous experience.