Hippocampal lesions interfere with long-trace taste aversion conditioning.

This series of experiments investigated the effects of dorsal and ventral hippocampal lesions on taste aversion learning. Although damage to the hippocampus did not affect the acquisition of a taste aversion when the conditioning procedure used a relatively standard interval between taste and illness, both types of lesions produced a deficit in taste aversion when a long interval (3 h) was interposed between taste exposure and induction of illness. In the same subjects, trace fear conditioning was selectively impaired by ventral lesions, whereas water maze performance was selectively impaired by dorsal lesions. The results replicate past dissociations of dorsal and ventral hippocampal function, and also suggest that the hippocampus has a less differentiated role in long-trace taste aversion learning.