Journal Article

Quadri-Pulse Theta Burst Stimulation using Ultra-High Frequency Bursts – A New Protocol to Induce Changes in Cortico-Spinal Excitability in Human Motor Cortex

Haug, Carolin, Jung, Nikolai H., Mall, Volker, Hoess, Catrina, Gleich, Bernhard, Siebner, Hartwig R., Gattinger, Norbert

2016

Overview

Patterned transcranial magnetic stimulation (TMS) such as theta burst stimulation (TBS) or quadri-pulse stimulation (QPS) can induce changes in cortico-spinal excitability, commonly referred to as long-term potentiation (LTP)-like and long-term depression (LTD)-like effects in human motor cortex (M1). Here, we aimed to test the plasticity-inducing capabilities of a novel protocol that merged TBS and QPS. 360 bursts of quadri-pulse TBS (qTBS) were continuously given to M1 at 90% of active motor threshold (1440 full-sine pulses). In a first experiment, stimulation frequency of each burst was set to 666 Hz to mimic the rhythmicity of the descending cortico-spinal volleys that are elicited by TMS (i.e., I-wave periodicity). In a second experiment, burst frequency was set to 200 Hz to maximize postsynaptic Ca2+ influx using a temporal pattern unrelated to I-wave periodicity. The second phase of sinusoidal TMS pulses elicited either a posterior-anterior (PA) or anterior-posterior (AP) directed current in M1. Motor evoked potentials (MEPs) were recorded before and after qTBS to probe changes in cortico-spinal excitability. PA-qTBS at 666 Hz caused a decrease in PA-MEP amplitudes, whereas AP-qTBS at 666 Hz induced an increase in mean AP-MEP amplitudes. At a burst frequency of 200 Hz, PA-qTBS and AP-qTBS produced an increase in cortico-spinal excitability outlasting for at least 60 minutes in PA- and AP-MEP amplitudes, respectively. Continuous qTBS at 666 Hz or 200 Hz can induce lasting changes in cortico-spinal excitability. Induced current direction in the brain appears to be relevant when qTBS targets I-wave periodicity, corroborating that high-fidelity spike timing mechanisms are critical for inducing bi-directional plasticity in human M1.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adolescent / Adult / Amplitudes / Authorship / Biology and Life Sciences / Brain / Brain research / Brain stimulation / Bursting / Calcium influx / Cortex (motor) / Cortex (temporal) / Electromyography / Engineering and Technology / Evoked Potentials - physiology / Evoked Potentials, Motor - physiology / Excitability / Excitation / Female / Health aspects / Humans / Long-term depression / Long-term potentiation / Long-Term Potentiation - physiology / Magnetic fields / Male / Medicine and Health Sciences / Motor cortex / Motor Cortex - physiology / Motor evoked potentials / Neurosciences / Pediatrics / Periodicity / Physical Sciences / Physiological aspects / Physiology / Plastic properties / Plasticity / Research and Analysis Methods / Temporal lobe / Transcranial magnetic stimulation / Transcranial Magnetic Stimulation - methods / Young Adult