Neuroplastic Alterations of the Motor Cortex by Caffeine

University Medical Center Goettingen

Status: Completed

Conditions: Brain Stimulation; Caffeine; Cortical Excitability

Treatments: Other: 200 mg caffeine tablet; Other: Non-active tablet

Study type: Interventional

Funder types: Other

Identifiers

NCT04011670

33/3/19

Details and patient eligibility

About

Caffeine is a psychostimulant drug. It acts as a competitive antagonist at adenosine receptors, which modulate cortical excitability as well. In deep brain stimulation (DBS), the production of adenosine following the release of adenosine triphosphate (ATP) explains the reduction of tremor. Binding of adenosine to adenosine A1 receptors suppresses excitatory transmission in the thalamus and hereby reduces both tremor-and DBS-induced side effects. Also, the effect of adenosine was attenuated following the administration of the 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX) adenosine A1 receptor antagonist. Therefore, the presence of a receptor antagonist such as caffeine was suggested to reduce the effectiveness of deep brain stimulation (DBS) in treating tremor and other movement disorders.

Based on this finding, the investigators hypothesize that the antagonistic effect of caffeine can tentatively block the excitatory effects of transcranial alternating current stimulation (tACS). The plasticity effects might differ among caffeine users and non- caffeine users depending on the availability of receptor binding sites.

Apart from that, a major issue in NIBS studies including those studying motor-evoked potentials is the response variability both within and between individuals. The trial to trial variability of motor evoked potentials (MEPs) may be affected by many factors. Inherent to caffeine is its effect on vigilance. In this study, the investigator shall monitor the participant's vigilance by pupillometry to (1) better understand the factors, which might cause variability in transcranial excitability induction studies and (2) to separate the direct pharmacological effect from the indirect attentional effect of caffeine.

Enrollment: 30 patients

Sex: All

Ages: 18 to 45 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

1. Male and female healthy participants between the ages of 18-45.
2. Right-handed (Oldfield 1971).
3. Free willing participation and written, informed consent of all subjects obtained prior to the start of the study.
4. Participant's weight is above 60 kg

Exclusion criteria

1. Age < 18 or > 45 years old;
2. Left hand dominant;
3. Evidence of a chronic disease or history with a disorder of the nervous system
4. History of epileptic seizures;
5. Pacemaker or deep brain stimulation;
6. Metal implants in the head region (metal used in the head region, for example, clips after the operation of an intracerebral aneurysm (vessel sacking in the region of the brain vessels), implantation of an artificial auditory canal);
7. Cerebral trauma with loss of consciousness in prehistory;
8. Existence of a serious internal (internal organs) or psychiatric (mental illness)
9. Alcohol, medication or drug addiction;
10. Receptive or global aphasia (disturbance of speech comprehension or additionally of speech);
11. Participation in another scientific or clinical study within the last 4 weeks;
12. Pregnancy
13. Breastfeeding
14. Intolerance to caffeine or coffee products
15. Participant who has abnormal heart activity from an electrocardiography (ECG) finding
16. Weight is less than 60 kg

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Double Blind

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30 participants in 2 patient groups, including a placebo group

Caffeine group

Active Comparator group

Description:

Participants will receive a caffeine tablet and all electrical stimulations in a random order (tACS 140 Hz at 1 mA and sham tACS). Participant's vigilance status will be monitor based on active vigilance condition or passive vigilance condition.

Treatment:

Other: 200 mg caffeine tablet

Placebo group

Placebo Comparator group

Description:

Participants will receive a placebo tablet and all electrical stimulations in a random order (tACS 140 Hz at 1 mA and sham tACS). Participant's vigilance status will be monitor based on active vigilance condition or passive vigilance condition.

Treatment:

Other: Non-active tablet