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Exploring the Cortical Hemodynamic Variability of Prefrontal iTBS: a Concurrent TBS/fNIRS Study
Sponsor: The Hong Kong Polytechnic University
Summary
An increasing number of studies have used the intermittent theta-burst stimulation (iTBS) protocol to investigate neural plasticity non-invasively in the prefontal cortex in healthy humans and in patients with psychiatric disorders. However, the variability in the neurophysiological response to iTBS stimulation is high. The cause of this variability is multifactorial and to some degree still unknown. Therefore, the current study explores inter- and intra-individual factors that are potentially moderating iTBS-induced excitability changes. A greater understanding of these determinants would be highly valuable for optimizing the therapeutic application of iTBS.
Key Details
Gender
All
Age Range
18 Years - 60 Years
Study Type
INTERVENTIONAL
Enrollment
40
Start Date
2023-10-18
Completion Date
2024-12-31
Last Updated
2026-09-17
Healthy Volunteers
Yes
Conditions
Interventions
Intermittent theta burst stimulation (iTBS)
The iTBS protocol consists of 20 trains of stimulation. Each train comprises ten 3-pulse bursts, delivered at an intra-burst frequency of 50 Hz, with a 5 Hz overall frequency, followed by 8 seconds of rest. A total of 600 pulses (10\*3\*20) will be administered in this 3-minute iTBS protocol. Concurrent TBS/fNIRS stimulation will be applied over the left DLPFC at an intensity of 90% of the resting motor threshold (RMT), which is considered appropriate to ensure compliance and elicit robust DLPFC activation. Considering that the fNIRS optode beneath the coil increases the distance between the TMS coil and the skull by 10 mm, we will use the equation AdjMT% = MT + 2.8 \* (Dsitex - Dm1). Therefore, 2.8 \* 10 = 28% will be added to the normal intensity. The stimulation site over the DLPFC will be determined by the MNI coordinate (x-38, y+44, z+26) reported in previous studies.
Locations (1)
The Hong Kong Polytechnic University
Hong Kong, Hong Kong