Primed vs Unprimed Facilitatory and Depressive Paired Associative Stimulation

Primed vs Unprimed Facilitatory and Depressive Paired Associative Stimulation

Following brain injury (e.g. stroke), application of non-invasive brain stimulation may improve rehabilitative efforts. However, the most effective method of non-invasive brain stimulation is unknown. Paired associative stimulation (PAS) is a method of non-invasive brain stimulation that pairs an electrical peripheral nerve stimulus with a magnetic stimulus to the head. This method can be applied in a manner that increases (facilitates) or decreases (depresses) excitability within the brain. Furthermore, applying two consecutive PAS sessions within minutes of each other (called primed PAS) may augment changes in excitability more than a single PAS session alone.

Thus, the purpose of this study is to compare the effect of a double PAS session (primed PAS) to the effect of a single PAS session (unprimed PAS) and a sham PAS session in healthy individuals.

Inclusion Criteria:

• ≥ 18 and ≤ 30 years of age
• Elicitable motor evoked potential from the motor cortex contralateral to the dominant hand
• Elicitable N20 sensory evoked potential

Exclusion Criteria:

• History of neurological disease
• Seizure within the past 2 years
• Currently taking epileptogenic medication
• Peripheral neuropathy
• Cognitive impairment and/or major psychiatric disorder
• Metal in the head (dental permitted)
• Pacemaker or other indwelling devices
• Pregnancy