Prof. dr. Judith Homberg (Radboud MC)

The ability to perceive and process environmental stimuli in order to respond to them is one of the most fundamental traits observed across species and essential for survival. It is a trait that is at the root of virtually all behaviour and enables an individual to recognize and differentiate various environmental stimuli and adapt to changes. While all organisms are sensitive to the environment, some are more sensitive than others. Environmental sensitivity has been attributed to an increased ability to perceive and process information through an increased sensitivity of the central nervous system. However, these descriptions are vague, and it is unclear how a more sensitive brain is functioning from a neurobiological perspective. One key molecule influencing environmental sensitivity across the animal kingdom is serotonin. The well characterized constitutive serotonin transporter (5-HTT) knockout rat model exhibiting increased extracellular serotonin levels and show is increased environmental sensitivity. In my presentation I will present a series of published as well as unpublished data to demonstrate the sensitivity of the animals to both negative (e.g. stressful) and positive (e.g. rewarding) environmental stimuli, and the underlying behavioural and neural mechanisms.