This study aims to determine whether levodopa is effective in boosting learning and memory in healthy subjects and patients with dementia or Mild Cognitive Impairment.

We also examine in healthy subjects using functional magnetic resonance imaging which brain regions mediate improved learning after levodopa administration.

Prior work of our group shows that the dopamine precursor levodopa markedly improves word learning success in healthy subjects. In this randomized, placebo-controlled, double-blind trial, we probe whether administration of levodopa improves learning performance as compared to placebo administration on neuropsychological tests and in an associative learning paradigm. We postulate that levodopa improves learning success and memory performance in healthy subjects, while the effect in patients with dementia or Mild Cognitive Impairment might depend on other factors, including severity of memory impairment.

Inclusion criteria for patients with dementia:

• Patients: clinical diagnosis of AD or mild cognitive impairment
• primary language German

Exclusion Criteria for healthy subjects and patients with dementia/MCI:

• Known allergy to levodopa or tetrazine
• History of medication/drug abuse
• Acute nicotine withdrawal or > 15 cigarettes per day
• > 6 cups/glasses of coffee, caffeine drinks or energy drinks per day
• > 50 grams of alcohol per day
• Severe hypertonia (systole >160 mm Hg)
• Severe arteriosclerosis
• Diabetes, asthma, or glaucoma
• Severe hearing disability
• no focal brain lesions
• Premorbid depression or psychosis
• Medication with dopamine agonists or antagonists
• Parkinsonian symptoms