Background: Light is the most important regulator of circadian rhythm. Naturalistic light, which contains the spectrum of sunlight throughout the day, has been shown to have a positive impact on mental states such as depression and fatigue in stroke and other diseases requiring long-term hospitalization. Depression and fatigue are very common complications after stroke, with a frequency of 30% and 85%, respectively. Both are significantly related to reduced quality of life and early death. Both the causes and pathophysiology behind these complications are unknown, but it is assumed that disturbances (inflammation and cell death) in brain areas and brain networks related to arousal, sleep, circadian rhythm, and the frontal lobe play a role. The hypothesis is that it is possible to detect changes in brain networks related to depression and fatigue by MRI, and that naturalistic light will affect these changes. Method: Stroke patients requiring a minimum of 10 days of rehabilitation are transferred to a neurorehabilitation unit with naturalistic lighting. Examination: Validated tests for fatigue, depression, sleep and cognitive functions. Pathophysiological studies: * MRI focusing on cerebral blood flow, metabolism, and cerebral networks. * Spinal fluid analyses for hormones and markers involved in immunological response as well as wakefulness/arousal and depression. * Sleep assessments.