Innately aversive experiences profoundly reshape brain function, generating emotional states that coordinate physiological responses, drive behavior, and form lasting memories. Beyond simple reactions, aversive events can also give rise to more complex emotions through the brain’s evaluation of sensory and interoceptive-bodily information in light of past experiences and the organism’s current state. Dysregulation of emotional processing systems underlies psychiatric conditions such as depression, anxiety and trauma related disorders.

The Johansen Lab investigates the brain circuit and neural coding mechanisms that transform aversive experiences into both simple and complex emotional states. We study how these processes regulate memory formation and guide adaptive behavior and how they are disrupted in psychiatric disease. To do this, we combine sophisticated behavioral assays with cutting-edge approaches, including high-density in vivo electrophysiology, large-scale calcium imaging, circuit-specific optogenetics, viral-based anatomical tracing, and computational modeling and analysis.

Our aim is to uncover the specific neural mechanisms underlying these processes while also identifying general principles of neural circuit function, coding, and plasticity. By doing so, we seek to provide a mechanistic understanding of emotion, learning and memory and decision-making, core aspects of human experience with direct implications for advancing treatments for psychiatric disorders such as depression.