Hippocampal formation is an structure of the brain localised in the temporal lobe. It has important functions related to the creation of memories, space memory, orientation and speech. In this first year of the thesis we are doing a model to study the effet of an inhibitory population in the dentate gyrus, one basic component of the hippocampus. The objective is based on the determination of plausible mechanisms to explain experimental results obtained by the group of Dr. Santiago Canals at the Instituto de Neurociencias de Alicante.