Role of the Supraspinal Opioidergic Circuit in Prefrontal TMS-Induced Analgesia

NCT ID: NCT01643798

Last Updated: 2014-04-15

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 15 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2011-01-31
• Study Completion Date: 2012-06-30

Brief Summary

Studies have shown that transcranial magnetic stimulation (TMS), a non-invasive form of brain stimulation, can reduce pain in the laboratory and in the clinic. The purpose of this study is to investigate how TMS relieves pain and affects pain circuitry in the brain. One of the primary study hypotheses is that opioid blockade will significantly reduce the pain relief produced by left prefrontal cortex TMS.

Detailed Description

Non-invasive forms of brain stimulation such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) are currently being investigated as alternative or adjunctive therapies for pain. Clinical interest in these techniques continues to grow because of rising opiate abuse and inadequate pain management strategies. Despite this enthusiasm, studies on the efficacy of repetitive TMS (rTMS) for pain have produced mixed results. Some of the most promising and informative research has focused on rTMS for perioperative pain. In two different postoperative studies, a single session of left dorsolateral prefrontal cortex (DLPFC) rTMS after gastric bypass surgery reduced morphine self-administration by 40% when compared to sham stimulation. These data are particularly fascinating given the role of the DLPFC in top-down pain processing.

Centered at the juncture of Brodmann Areas (BAs) 9 and 46, the DLPFC remains a popular therapeutic target for rTMS given its accessible location and presumed role in high-order cognition and emotional valence. Animal and human studies suggest that cingulofrontal regions like DLPFC may modulate pain perception via recruitment of opioidergic midbrain and brainstem structures like the periaqueductal gray (PAG) and the rostroventromedial medulla (RVM), respectively. These data outline the functional circuitry that might be involved in the analgesic effects of DLPFC rTMS.

While many studies aim to evaluate the clinical efficacy of DLPFC rTMS for pain management, few have examined how it affects pain processing. Imaging the cerebral signature of pain before and after left DLPFC rTMS might reveal information about pain circuitry and help to elucidate the mechanism by which prefrontal rTMS may produce analgesia. Previous studies suggest that opioid blockade abolishes left but not right DLPFC rTMS-induced analgesia. In this study, our a priori hypothesis was that left DLPFC rTMS would attenuate blood oxygenation-level dependent (BOLD) signal response to painful stimuli in pain processing regions. More specifically, we anticipated that midbrain and medulla BOLD signal changes induced by left DLPFC rTMS would be abolished by pretreatment with the μ-opioid antagonist naloxone.

Conditions

Pain

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: TRIPLE

Study Groups

Saline

Participants received intravenous saline immediately prior to sham and real rTMS of the left dorsolateral prefrontal cortex. The parameters of the stimulation paradigm are as follows: 10 Hz, 5 seconds on, 10 seconds off, 20 minutes, 4000 pulses).

Group Type: PLACEBO_COMPARATOR

Sham rTMS

Intervention Type: PROCEDURE

The eSham system was implemented in conjunction with a specialized Neuronetics sham TMS coil. This coil has a metal plate hidden inside of it that blocks the magnetic field from affecting the brain. Scalp electrodes were used to mimic the feel of real rTMS. This approach has been validated in previous studies.

Real rTMS

Intervention Type: PROCEDURE

An iron-core, solid-state figure-of-8 coil was used to stimulate the dorsolateral prefrontal cortex. The site of stimulation was estimated using the Beam F3 method based on the 10-20 EEG system.

Naloxone

Participants received intravenous naloxone (0.1mg/kg) immediately prior to sham and real rTMS of the left dorsolateral prefrontal cortex. The parameters of the stimulation paradigm are as follows: 10 Hz, 5 seconds on, 10 seconds off, 20 minutes, 4000 pulses).

Group Type: ACTIVE_COMPARATOR

Sham rTMS

Intervention Type: PROCEDURE

The eSham system was implemented in conjunction with a specialized Neuronetics sham TMS coil. This coil has a metal plate hidden inside of it that blocks the magnetic field from affecting the brain. Scalp electrodes were used to mimic the feel of real rTMS. This approach has been validated in previous studies.

Real rTMS

Intervention Type: PROCEDURE

An iron-core, solid-state figure-of-8 coil was used to stimulate the dorsolateral prefrontal cortex. The site of stimulation was estimated using the Beam F3 method based on the 10-20 EEG system.

Interventions

Sham rTMS

The eSham system was implemented in conjunction with a specialized Neuronetics sham TMS coil. This coil has a metal plate hidden inside of it that blocks the magnetic field from affecting the brain. Scalp electrodes were used to mimic the feel of real rTMS. This approach has been validated in previous studies.

Intervention Type: PROCEDURE

Real rTMS

An iron-core, solid-state figure-of-8 coil was used to stimulate the dorsolateral prefrontal cortex. The site of stimulation was estimated using the Beam F3 method based on the 10-20 EEG system.

Intervention Type: PROCEDURE

Other Intervention Names

Neuronetics Model 2100 Therapy System; Neuronetics Model 2100 Therapy System

Eligibility Criteria

Inclusion Criteria

• healthy volunteers
• no history of depression or pain
• no metal in body
• no medications that lower seizure threshold

Exclusion Criteria

• history of depression or pain
• history of seizures or epilepsy
• metal implants in body
• medications that lower seizure threshold
• psychiatric medications

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 45 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

National Institute on Drug Abuse (NIDA)

NIH

Sponsor Role: collaborator

Medical University of South Carolina

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Joseph J Taylor

Role: STUDY_DIRECTOR

Medical University of South Carolina

Locations

Medical University of South Carolina

Charleston, South Carolina, United States

Countries

United States

Other Identifiers

1F30DA033748-01

Identifier Type: NIH

Identifier Source: secondary_id

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1F30DA033748

Identifier Type: NIH

Identifier Source: org_study_id

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