Just which networks in the brain give rise to negative emotions (aversion) and chronic stress have long been unknown to science.
By using a combination of advanced techniques, such as Patch-seq, large-scale electrophysiology (Neuropixels) and optogenetics (see factbox), KI researchers Konstantinos Meletis and Marie Carlén and their team have been able to map out a specific neuronal pathway in the mouse brain leading from the hypothalamus to the habenula that controls aversion.
The researchers used optogenetics to activate the pathway when the mice entered a particular room, and found that the mice soon started to avoid the room even though there was nothing in it.