To support the development of a differential diagnosis of insomnia, structural and functional brain connectivity in insomnia patients with different levels of hyperarousal will be investigated and related to sleep variables. Investigators will compare the insomnia group to a normal sleeping control group. Investigators expect that the emotion processing circuit (amygdala-ventromedial prefrontal cortex) is a) more affected in insomniacs compared to normal sleeping controls and b) the directionality of this effect to depend on the level and type of hyperarousal in insomniacs. Further, investigators expect c) amygdala activity to be positive correlated with physiological hyperarousal level and d) prefrontal activity to be positively correlated with cognitive-emotional hyperarousal level. Investigators expect a higher physiological hyperarousal level to be reflected in affected afferent pathways of the amygdala towards the ventromedial prefrontal cortex and investigators expect higher cognitive-emotional hyperarousal to be related to affected efferent pathways from the ventromedial prefrontal cortex to the amygdala. Investigators expect sleep quality to play a mediating role in both types of hyperarousal and their brain activation patterns in insomnia patients and normal sleeping controls.