Important events of our lives are surrounded by strong emotions. Either accompanied by the positive feelings of joy, reward or satisfaction or by the negative feelings of grief, despair or sadness, we remember these events for a lifetime. Based on these experiences, we modify our future actions to enjoy more events with positive outcome and we try to avoid physically or emotionally harmful situations. Approaching of rewarding and avoidance of aversive events are ancient, evolutionary conserved motivations defining our behavior. The emotions bound to the experiences of our life arise in the brain, via interactions of neurons interconnected within and between different brain areas. Identification of these circuits and their cellular components, and deciphering the mechanisms defining emotions and related behavior is an intensively studied research field of our days.
Studying the acquisition of experiences accompanied by negative emotions lies in the core of my current research. I am interested about the build-up of the neuronal circuitry controlling the development of aversion and fear. Furthermore, I examine the cellular mechanisms of emotional learning and the formation of related long-term memories based on fearful or aversive events. To study these phenomena, I use a repertoire of state-of-the-art behavioral tests in the awake mice combined with optogenetics or functional imaging. In parallel, I use quantitative immuno-labeling of key molecules combined with high-resolution confocal and electron microscopy to analyze the underlying structural and functional anatomical background.
The basolateral amygdala (BLA) plays an essential role in associative learning and in the related long-term memory formation. Both the sensory and the emotionally salient component of important life events reach the BLA, where local circuit computational mechanisms help in the appropriate association of these inputs. This learning mechanism allows to predict the possible future occurrence of the relevant event based on the related predictive sensory cues.
Recently performed experiments show that the principal neurons of the BLA change their cellular activity heterogeneously during learning. In this project, we aim to decipher the cellular mechanisms and molecular background that may underlie this heterogeneity. To achieve this, we image the cellular activity of BLA neurons in awake mice during learning, followed by the identification and quantitative molecular screening of neurons based on their plasticity phenotypes.
The median raphe region in the brainstem plays an important role in the regulation of mood, motivation and learning. We have recently described a population of glutamatergic neurons in the mouse median raphe region that directly and effectively controlled the acquisition of negative experience. Selective stimulation of these cells promoted active avoidance or aggressive behavior, while selective inhibition of these cells during fear learning impaired appropriate fear memory formation.
In this project we image and analyze the activity of glutamatergic median raphe neurons during fear learning to better understand their contribution to the development of aversive behavior and correlated memory formation.