Brain disorders affecting memory and cognition are one of the main healthcare problems of our aging society, which sparked emergence of the world-wide neuroscience projects to develop new technologies to understand and treat cognitive Deficits. In this project, I propose to study declarative memory at the brain’s core level of neuronal assemblies with concurrent tracking of eye movements and pupil dilation in patients. Innovative techniques for large-scale Electrophysiology will be employed to record and stimulate activities of specific neuronal assemblies. The goal is to map and Modulate the neuronal assembly activities that reflect encoding of memories for specific Stimuli and find an optimal approach to enhance it with direct electrical stimulation.The results of this research have potential applications for investigating and treating cognitive Deficits in a range of brain disorders, leading to development of brain-machine interfaces for therapeutic brain stimulation.