The Role of Circadian Factors in Regulation of Neuroplasticity in Ischemic Stroke (Interventional)

Inclusion Criteria: * acute (symptom onset to admission \<1 days) ischemic stroke * ischemic stroke affecting the branches of anterior cerebral artery, middle cerebral artery and posterior cerebral artery * age 18-80 years * moderate or severe stroke (National Institutes of Health Stroke Scale, NIHSS\>=5) * intravascular stroke treatment with thrombolysis or thrombectomy leading to satisfactory reperfusion (if applicable) * informed consent Exclusion Criteria: * secondary parenchymal hemorrhage (\>hemorrhage index (HI)-2) * clinically unstable or life-threatening conditions * previous stroke in the last 6 months * known progressive neurological diseases * known psychiatric diseases * concomitant benzodiazepine medication * drug or alcohol abuse * pregnancy * inability to participate in the study * severe sensory aphasia * melatonin intake at/before admission * light therapy use at/before admission * blindness * severe sleep-disordered breathing (apnea-hypopnea index \>=30/h) * contraindications to light therapy (severe retinopathy, epilepsy, porphyria, intake of drugs with photosensitizing effects) * contraindications to melatonin intake (severe bronchial asthma, severe autoimmune disorders, chronic kidney disease 3b stage and higher, leukosis) * congestive heart failure with reduced ejection fraction (\<=45%) or New York Heart Association (NYHA) classification III-IV functional class.