This study aims to determine whether levodopa, in combination with a high frequency training of (grammatical) rules, is effective in boosting learning success in healthy subjects and whether this kind of training in combination with levodopa improves reading and spelling abilities of patients with dyslexia.

Prior work by our group shows that d-amphetamine and the dopamine precursor levodopa markedly improve word learning success in healthy subjects. In this randomized, placebo-controlled, double-blind trial, we probe whether daily administration of levodopa, coupled with a training of grammatical rules, improves the training success in healthy adults as compared to placebo administration. In the second step of this study, patients with dyslexia will be trained with the identical protocol. We postulate that the combination of intensive training in language rules and levodopa improves the reading, writing, and spelling abilities of patients with dyslexia.

Inclusion Criteria:

• Right-handedness
• Age between 18-35 years
• Primary language: German

Exclusion Criteria:

• Known allergy to levodopa or tetrazine
• History of medication/drug abuse
• Acute nicotine withdrawal or > 10 cigarettes per day
• >6 cups/glasses of coffee, caffeine drinks or energy drinks per day
• >50 grams of alcohol per day
• Hypertonia
• Arteriosclerosis
• Diabetes, asthma, or glaucoma
• Psychiatric disease
• Neurologic disease
• Other medication