Control of fear in the brain decoded
When healthy people are faced with threatening situations, they react with a suitable behavioural response and do not descend into a state of either panic or indifference, as is the case, for example, with patients who suffer from anxiety. With the help of genetic studies on mice, scientists from the Max Planck Institute of Psychiatry have discovered two opposing neuronal regulatory circuits for the generation and elimination of fear. Both are controlled by the stress-inducing messenger substance corticotropin-releasing hormone (CRH) and its type 1 receptor (CRHR1). The availability of these factors in neurons that release glutamate in brain areas of the limbic system activates a neuronal network which causes anxiety behaviour. Conversely, in dopamine-releasing neurons in the mid-brain, these factors give rise to behaviour that reduces fear. Because disorders of the stress factors may be observed in many patients with affective illnesses, the scientists suspect that the pathological alteration of...