The goal of this project is to determine the effects of 6-week dietary supplementation with one of two doses of citicoline (250 mg/d, 500 mg/d) or placebo on prefrontal cortical membrane dynamics (31P-MRS) and event-related functional activation (fMRI) in healthy middle-aged adults.

To determine the effect of citicoline supplementation on cortical structure and function in healthy middle-aged adults. Test 1: The effect of citicoline (500 mg/d) compared with placebo on event-related anterior cingulate cortex (ACC) activation during sustained attention by fMRI. Test 2: The effect of citicoline (500 mg/d) compared with placebo on reaction time and increasing accuracy on the sustained attention task (CPT-IP). Test 3: The effect of citicoline compared with placebo on phosphodiester (PDE) and b-NTP levels in the ACC by 31P-MRS. Test 4: ACC activation and CPT-IP performance (fMRI) and ACC PDE levels (31P-MRS) following high-dose citicoline (500 mg/d) compared with placebo at Week 3. Test 5: The effect of low-dose citicoline (250 mg/d) compared with placebo on an ACC activation and CPT-IP performance (fMRI) and ACC PDE levels (31P-MRS). Test 6: Among all subjects (n=60), the relationship between baseline red blood cell (RBC) omega-3 fatty acid (EPA+DHA) levels and ACC activation, ACC PDE levels, or the effects of citicoline.

Inclusion Criteria:

• Provision of written informed consent;
• Ages 40-60 years old;
• Right handed.
• If female, not pregnant (as determined by a positive pregnancy test); and agrees to use one of the following methods of birth control: abstinence from sexual intercourse, barrier (diaphragm or condom), or oral/injectable contraceptive;

Exclusion Criteria:

• Contraindication to an MRI scan (i.e., braces, claustrophobia, pacemaker etc);
• A history of a major medical (e.g., diabetes) or neurological illness (e.g., epilepsy);
• Body mass index (BMI) ≥ 30;
• An IQ <75 and >130;
• A positive urine drug test (nicotine dependence is permitted);
• Personal history of a DSM-5 Axis I psychiatric disorder;
• Requiring treatment with a drug which might obscure the action of the study treatment.