Clinical trial NCT04031105: Probing Homeostatic Plasticity With Priming Theta-burst Stimulation of the Dorsolateral Prefrontal Cortex
Official title: Probing Homeostatic Plasticity With Priming Theta-burst Stimulation of the Dorsolateral Prefrontal Cortex
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Depression Minor
Lead sponsor: The Hong Kong Polytechnic University
Sponsor class: OTHER
First posted: 2019-07-24
Enrollment: 160
Sex: ALL
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Randomized, single blind, parallel group experiment
Primary purpose: BASIC_SCIENCE

Brief summary: Priming stimulation is a highly promising tool to boost the beneficial effects of therapeutic repetitive transcranial magnetic stimulation (rTMS) in psychiatry. The potentiating effects of priming stimulation, however, depend on the time interval between the priming and the test stimulation. Although it is known that too short and too long intervals have no effects, systematic studies that identify the time needed to maximize efficacy have not yet been done. Thus, there is a need for studies to investigate the effects of priming stimulation in order to fully utilize the potential benefits and advantages of this promising new rTMS protocol. This study will systematically investigate the neuromodulatory process underlying priming stimulation to enhance metaplasticity in the left dorsolateral prefrontal cortex (DLPFC) - one of the main targets for therapeutic rTMS - in individuals with subclinical depression.

The brain is a highly plastic organ and its activity can be influenced using rTMS. At the same time, the brain also has a mechanism - called homeostatic metaplasticity - which counteracts extreme plastic changes. Homeostatic metaplasticity therefore can limit the beneficial effects of brain stimulation interventions. However, priming stimulation protocols that include both a priming and a test stimulation session may utilize homeostatic metaplasticity to increase the beneficial effects of brain stimulation, although the optimal treatment parameters for priming are not known. Moreover, little is known about homeostatic metaplasticity in the DLPFC, an area that is particularly relevant for psychiatric conditions given its role in the top-down control of emotions. Here, the investigators will systematically study metaplasticity using priming theta-burst stimulation (TBS), a potent form of rTMS in the left DLPFC. Changes in blood oxygenation that signal brain activity changes will be assessed using functional near-infrared spectroscopy (fNIRS) at rest and during engagement in several cognitive tasks. The findings from this study will (1) elucidate the optimal time interval between priming and test stimulation; (2) elucidate the influence of priming TBS on emotion discrimination as well as executive function and its underlying brain activity in subclinical depression; and (3) validate homeostatic metaplasticity in the left DLPFC.

Detailed description: No detailed description

Eligibility criteria: Inclusion Criteria:

1. age 18-35
2. education level of primary six or above
3. right-handedness
4. normal or corrected-to-normal vision
5. being able to understand the verbal instructions
6. willingness to sign the informed consent form

Exclusion Criteria:

1. a history of seizures
2. current or past psychiatric disorders
3. current or past severe internal or neurological illness
4. ferromagnetic implants \<20cm from the head, cardiac pacemaker, deep brain stimulation and other common TMS exclusion criteria
5. history of substance dependence or abuse within the last 3 months
6. intake of any medication known to affect the excitation threshold (i.e., benzodiazepines, anticonvulsants).

Primary outcomes:
measure: Change in hemoglobin concentrations (Hb) during rest
timeFrame: Change from baseline Hb at 15 minutes post-stimulation
measure: Change in hemoglobin concentrations (Hb) while participants perform an emotion stroop task and verbal fluency task
timeFrame: Change from baseline Hb at 15 minutes after stimulation
Secondary outcomes:
measure: Change in reaction time during emotion stroop task
timeFrame: Change from baseline reaction times at 15 minutes after stimulation
measure: Change in the number of correctly responded colored words in the emotional Stroop task and correctly generated words in the verbal fluency task.
timeFrame: Change from baseline score at 15 minutes after stimulation
measure: Change in the number of correctly recognized emotion
timeFrame: Change from baseline score at 15 minutes after stimulation
Other outcomes:
Locations:
city: Hong Kong
country: Hong Kong
facility: The Hong Kong Polytechnic University
Study officials:
References: