The goal of the project is to better understand information processing in brain memory systems. Large scale neural networks build step by step complex representations of the surrounding world, stored in the patterns of neural activity. Eventually, these memory engrams get activated by poorly understood retrieval process. The main theme of the program will be a study of neural representations performed both by classical in vivo techniques of multiunit electrophysiology and by recent methods of cellular Calcium imaging in laboratory rodents while performing in cognitive tests. The work will focus on network memory state-changes as a model of memory retrieval in physiology and under the states simulating various human neuropathologies.