Attentional theories of hippocampal function (Douglas, 1972; Douglas & Pribram, 1966; Grastyan, Lissak, Madarasz, & Donhoffer, 1959; Kimble, 1968; Moore, 1979; Solomon & Moore, 1975) emphasize that the hippocampus is

involved in the modulation of the level of processing assigned to environmental stimuli. An important problem with most of these theories is that they do not specify the nature of interactions between attention and associative learning, and consequently, none of the theories can provide unequivocal predictions of the effects of hippocampal manipulations on classical conditioning. Typical hippo­ campal manipulations include hippocampal lesions (HL), hippocampal induction of long-term potentiation (LTP), hippocampal kindling, and hippocampal neural recording. Because the actual meaning of attention in classical conditioning depends on the particular model in which it is defined, a precise understanding of how attentional variables affect conditioning requires a computational model in which the variables are incorporated. Computational models should be able to describe normal conditioning and, with changes in their attentional variables, they should describe the consequences of different hippocampal manipulations.