Mariano A. Belluscio, Ph.D.

Research

The hippocampus in involved in various cognitive processes, including declarative memories and spatial navigation. An important aspect of those processes is the need to separate two or more multiple partially overlapping events. This procedure is known as pattern separation. The dentate gyrus is believed to be critical in this process. Our work is focused on the in vivo network patterns of dentate gyrus. By means of high density electrodes we were able to record from multiple extracellular unit activity as well as local field potentials (LFP) in the rat dentate gyrus. The experiments were performed under distinct behavioral states of the animal: awake during exploring, immobility and consummatory behaviors and rapid eye movement and slow wave sleep. During these different behavioral states LFP activity displays distinct characteristic patterns. We have analyzed the activity of different recorded neurons with respect to their relationship with the different LFP patterns as well as with the other simultaneously recorded cells. Also, we have measured the depth profiles of some distinctive LFP patterns to identify the current sources and sinks involved in their generation. These findings elucidate how the different types of dentate principal cells and interneurons contribute to cooperative patterns observed in the LFP and, indirectly, how these distinct patterns contribute to the behavioral function of the dentate gyrus.