This project examines the new hypothesis that persistent neuronal activity is present during sleep-related brain oscillations, and its possible function in memory formation.
To determine presence and repartition of persistent activity, membrane potential from individual identified neurons in the entorhinal cortex and connected areas in anesthetized and sedated mice will be recorded in-vivo, and their cell-specific activity will be related to concomitant cortical and hippocampal network activity. In parallel, suitable analysis-algorithms will be developed, potential generating mechanisms will be identified, and a computer model for the description of cellular-, network- and neuromodulatory components of persistent activity will be designed. Computermodel-based hypothesis are then to be tested by experimental induction of persistence on the single-cell and network level in the hippocampal formation. Further the influence of persistence on theta-oscillations and spike-timing in hippocampus as well as the interaction of hippocampal activity with cortical persistence will be examined. Finally the extended computer model is expected to explain the generation of persistent activity and its influence on cortico-hippocampal interaction and thereby on memory formation.

The following scientists take part in this collaboration:

• Thomas Hahn, Zentralinstitut für Seelische Gesundheit, Klinik für Psychiatrie und Psychotherapie, Mannheim
• Mayank Mehta, Dep. of Neurology, Dep. of Physics & Astronomy, UCLA, Los Angeles, USA