The functional role of altered olfactory network synchrony in the development of depression
1 MTA-SZTE ‘Momentum’ Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged H-6720, Hungary; 2Department of Neuropharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Aichi 467-8603, Japan; 3Neuroscience Institute, New York University, New York, New York 10016, USA
There is an increasing evidence showing that brain regions traditionally classified as parts of the olfactory network are involved in the pathophysiology of depression. Olfactory bulb (OB) is a major source of brain wide gamma oscillations. Decreased power and long-range desynchronization of gamma oscillations were recently found as potential biomarkers of major depression, thus we set out to investigate the functional role of gamma rhythms of olfactory origin in the development and treatment of depressive symptoms. Preliminarily, we investigated the coherency map between OB and multi-brain areas in intact Long-Evans rats. Then, we employed OB-driven closed-loop electrical stimulation in the piriform cortex (Pir) to probe the role of perturbed OB-Pir synchrony in the development of depressive symptoms. Animals with perturbed oscillations showed dramatically decreased sucrose preference (anhedonia), and there was a decreased trend of spontaneous movement in the home cage (reduced motivation). Together, these results may indicate the importance of perturbed OB-driven synchrony in depression-like behavior.