Neuronal plasticity and seizure spread in the entorhinal cortex and hippocampus of amygdala kindled rats

Abstract

The entorhinal cortex is the main input and output region for the hippocampus and forms with the DG, the cornu ammonis and the subicular regions a functional complex which is involved in learning and memory of explicit information, stress adaptation and sexually oriented cognitive tasks. With respect to learning and memory the entorhinal cortex-hippocampus complex displays different working modes. For storage of information the structure has to decide whether stored information is novel; before a memory trace is formed. Once information is stored the memory traces are still labile and therefore require consolidation. Stored information must be retrieved. Apart from the novelty detection mode, the storage mode, the consolidation mode and the retrieval mode the entorhinal cortex has also a distributor task as not all information reaching this complex is transferred to the hippocampus. Thus temporally structured information is usually thought to be processed in frontal cortex areas. Indeed a number of such behavioral tasks depend on intact information processing in the entorhinal and perirhinal cortex areas (Zola-Morgan et al., 1989). This requires that there is also a distributor mode which decides where information is stored.