Probing TBS-induced Neural Plasticity and Associated Effects on Learning

Study Overview
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Brief Summary
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Recent animal research indicates that excitatory brain stimulation opens a time window of increased neural plasticity that permits remodeling of neural representations. Repetitive transcranial magnetic stimulation (rTMS) may thus facilitate learning of new associations by reducing proactive interference but human research is missing. Therefore, it is the aim of this study to investigate the effects of intermittent theta-burst stimulation (iTBS), a potent form of excitatory brain stimulation, on associative memory. Twenty right handed healthy participants will receive 3 minutes of iTBS or sham stimulation of the left lateral parietal cortex after memorizing a set of 20 face-word associations. Recall capacity will be tested directly before and after stimulation. Participants will then learn a new combination of associations using the same set of stimuli, followed by an evaluation of their recall capacity. It is hypothesized that iTBS compared to sham stimulation will reduce recall capacity directly after the stimulation but increase recall capacity of the newly learned associations due to reduced proactive interference. This study may not only pave the way towards a new understanding of the mechanism of action of brain stimulation, but can also help in developing new treatment strategies for neuropsychiatric disorders.

Official Title
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Probing TBS-induced Neural Plasticity and Associated Effects on Learning

Conditions
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Healthy

Intervention / Treatment
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* Device: Theta-burst stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: education level of primary six or above right-handedness normal or corrected-to-normal vision Exclusion Criteria: seizures in medical history current or past psychiatric disorders or severe internal or neurological illness common TMS exclusion criteria substance abuse or dependence intake of medication that is known to affect the excitation threshold

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: single-blind parallel-group crossover design
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intermittent theta-burst stimulation<br>iTBS will be performed on the left lateral parietal cortex | Device: Theta-burst stimulation<br>* iTBS comprises 3-pulse 50-Hz bursts, applied every 200 ms (at 5 Hz) as described previously (Huang, Edwards et al. 2005) and consists of 2-second trains with an inter-train-interval of 8 seconds. We will repeat trains (30 pulses; 10 bursts) for 20 times to reach a total number of 600 pulses per session (3x10x20)<br>* Other names: Transcranial Magnetic Stimulation;|
| Active Comparator: Control stimulation<br>iTBS will be performed on the vertex | Device: Theta-burst stimulation<br>* iTBS comprises 3-pulse 50-Hz bursts, applied every 200 ms (at 5 Hz) as described previously (Huang, Edwards et al. 2005) and consists of 2-second trains with an inter-train-interval of 8 seconds. We will repeat trains (30 pulses; 10 bursts) for 20 times to reach a total number of 600 pulses per session (3x10x20)<br>* Other names: Transcranial Magnetic Stimulation;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in recall capacity | Change in the number of correct associations of a face-word association memory test | Change from baseline to directly after stimulation ( 6 min after baseline) |