The Kamin effect in hippocampal-lesioned animals

Abstract

Ventral hippocampal and sham-operated rats were given one-way active-avoidance training follo\le d by relearning either 5 min, 1 h, or 24 h later. Both ventral hippocampal and sham-operated rats showed deficits in active-avoidance relearning performance 1 h after original avoidance acquisition. The failure of ventral hippocampal lesions to influence avoidance performance 1 h following original avoidance acquisition may indicate that neither the adrenal-pituitary nor the adrenergic-cholinergic systems are essential for the occurrence of the Kamin effect.

Fornix lesions, plasma ACTH levels, and shuttle box avoidance in rats.

“…In addition, the results of Experiment 1 suggest that the Kamin effect can be eliminated by disruption of the fornix, at least if two-way active avoidance is used as the behavioral paradigm. However, these findings are not compatible with the observation of Klein et al (1975), who found that ventral hippocampal lesions did not prevent the Kamin effect. Klein et al used a one-way active avoidance task, whereas a two-way task was used in the present experiment.…”

“…Experiment 1 was conducted to replicate the effect of fornix lesions in rats on acquisition of shuttle box avoidance and to determine the effect of these lesions on performance of the response 1 hr and 24 hr after initial acquisition. One investigation has been published concerning the effects of hippocampal damage on the "Kamin effect" (Klein, Murphy, & Freeman, 1975), and the lesion did not alter the effect. However, the lesions produced in the experiment of Klein et al were limited to a small part of the ventral hippocampus.…”

The Hippocampus as a Cognitive Map

“…The fact that corticosterone concentrates in cell nuclei during this time and has been implicated in protein synthesis ) raises the exciting possibility that this hormone is in some way involved in the plasticity underlying long-term memory changes in the mapping system. The failure to find an effect of hippocampal lesions upon the Kamin pattern (Klein et al 1975) argues against this possibility. * * Several recent review articles treat the interaction between the hippocampus and various hormone systems (McEwen, Gerlach, and Micco 1975, Bohus 1975, McGowan-Sass and Timiras 1975, Van Hartesveldt 1975.…”

“…We do not feel that these time-dependent changes basically affect the argument we are making here. Recently, Klein, Murphy, and Freeman (1975) have shown that the Kamin effect is intact in rats with hippocampal lesions.…”