Emotionally salient events can lead to formation of persistent vivid memories, which recruit a brain-wide network of cells communicating through specific rhythmic network activity patterns. The ventral portion of the hippocampus is a central hub in this network as it generates within its autoassociative CA3 network typical patterns of gamma oscillations and sharp wave ripples. It is also intimately linked both anatomically and physiologically with the amygdala as a key region of emotion processing. Both areas and their interaction are controlled through the septal cholinergic systems mediating stress, arousal and different activity modes during sleep. The neuronal circuits in the ventral hippocampus thus coordinate cellular and network activities that are associated with reactivation of fear memory engrams. Thus balanced oscillatory communication within and across these neuronal circuits is crucial for formation and long-term storage of healthy emotional memories. Deficits in these functions on the other hand can provoke maladaptive behavior and lead to the development of fear and anxiety disorders such as post traumatic stress disorder. In this proposal, we aim to tackle the question how the ventral hippocampal network oscillations and its synergy with the amygdala mediate fear memory consolidation. We hypothesize that augmented network oscillations in the ventral hippocampus might be a risk factor for exaggerated fear memory and provide a window for amygdalar modulation on the ventral hippocampus during memory storage. We use state-of-the-art pharmaco- and optogenetic intervention methods in an oscillatory-state dependent
manner to interrogate the underlying mechanisms and to develop strategies for targeted intervention.
01.06.2018 – 31.05.2021