Interhippocampal transfer in passive avoidance task modifies metabolic activity in limbic structures

The hippocampus is probably the most studied brain structure regarding memory. Each brain hemisphere contains one hippocampus, and subjects with unilateral hippocampal lesions can perform adequately in several behavioral tasks. This property allows studying how both hippocampi interact. In this work, we show that the information acquired in a passive avoidance task with one hippocampus can be retrieved and used by the brain when the hippocampal side involved in the acquisition is blocked with TTX. The pre-exposition to the context is decisive. By combining behavioral tasks and cytochrome oxidase histochemistry we demonstrated that several brain structures, including the hippocampus, amygdala and other related regions, change their activity under the above-mentioned treatments.