Further implications of a computational model of septohippocampal cholinergic modulation in eyeblink conditioning

Abstract

Previously we have shown that Gluck and Myers's (1993) corticohippocampal model could be extended to incorporate Hasselmo and Schnell's (1994) hypothesis that septohippocampal cholinergic processes regulate the amount of information storage in hippocampus. The generalized model could account for the effect of the anticholinergic drug scopolamine in delaying onset of eyeblink conditioning (Myers et al., 1996). Here, we show that the model also accounts for additional eyeblink results, including quick recovery after scopolamine is removed, preserved latent inhibition, learned irrelevance and extinction under scopolamine, and no effect of systemic scopolamine after hippocampal lesion. Additionally, the model is consistent with data concerning localized scopolamine injections to the medial septum, the lateral septum, and the hippocampus and their effect on eyeblink conditioning.