Non-invasive Neuromodulation in Healthy Subjects
Conditions
Keywords
MRI, MRS, rTMS
Brief summary
The aim of this project is to increase our understanding of how two different protocols of repetitive transcranial magnetic stimulation (rTMS), inhibitory (1 Hz) and excitatory (5 Hz), applied over the primary motor cortex of the presumed dominant hemisphere, affect functional connectivity and neurochemistry in the brain.
Detailed description
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation method which is effective for treating both psychiatric and non-psychiatric disorders, such as posttraumatic stress disorder, obsessive compulsive disorder, pain syndromes and for improving motor function in neurodegenerative diseases or following stroke. rTMS uses series of brief pulses of magnetic field applied to the surface of the head for a period of time (e.g. 20 minutes). The effects of rTMS are transient, and critically dependent upon the location, frequency and intensity of stimulation. Several studies have provided evidence that rTMS can influence the excitability and function of neurons (neuromodulation) for up to one hour, both near to, and distant from, the site of stimulation. However it is still unclear how these transient local and distant changes in function induced by specific rTMS protocols are mediated. In this project we will combine expertise in Magnetic Resonance Imaging (MRI), Magnetic Resonance Spectroscopy (MRS) and rTMS neuromodulation to develop and test protocols for examining the changes produced by non-invasive brain stimulation on healthy subjects. rTMS will be applied outside the scanner using standard TMS coils and MRI/S at 7 Tesla will be acquired before and immediately after rTMS. Our aim is to increase the understanding of how the two different rTMS protocols, inhibitory (1 Hz) and excitatory (5 Hz), applied over the primary motor cortex of the presumed dominant hemisphere, affect functional connectivity and neurochemistry in the brain.
Interventions
DEVICEInhibitory rTMS (1 Hz)
Participants receive rTMS at a rate of 1 Hz, applied with a 70-mm figure-eight TMS coil connected to a stimulator, over the motor cortex hotspot contralateral to the dominant arm for 20 minutes at an intensity of 90% resting motor threshold (RMT) for a total of 600 TMS pulses. The total number of stimuli applied is well within the published safety guidelines for use of rTMS. rTMS is applied outside the scanner, whereas functional connectivity and neurochemistry are measured with MRI and MRS, respectively, at 7 Tesla. The MRI/MRS data are collected right before and immediately after the inhibitory rTMS intervention.
DEVICEExcitatory rTMS (5 Hz)
Participants receive rTMS at a rate of 5 Hz, applied with a 70-mm figure-eight TMS coil connected to a stimulator, over the motor cortex hotspot contralateral to the dominant arm for 20 minutes at an intensity of 90% RMT for a total of 600 TMS pulses. The total number of stimuli applied is well within the published safety guidelines for use of rTMS. rTMS is applied outside the scanner, whereas functional connectivity and neurochemistry are measured with MRI and MRS, respectively, at 7 Tesla. The MRI/MRS data are collected right before and immediately after the excitatory rTMS intervention.
Sponsors
University of Minnesota
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
21 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
Those volunteers who are evaluated as normal and not met
Exclusion criteria
will be potential candidates for this study.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Percent Change of GABA Concentration in a Voxel Encompassing the Left Motor Cortex, Measured at 30 Min After rTMS | Baseline/Pre-rTMS and 30 min after rTMS | GABA concentration is quantified with MRS at 7 Tesla. Percent change of GABA concentration is calculated from baseline (i.e., pre-rTMS). |
| Percent Change of GABA Concentration in a Voxel Encompassing the Right Motor Cortex, Measured at 60 Min After rTMS | Baseline/Pre-rTMS and 60 min after rTMS | GABA concentration is quantified with MRS at 7 Tesla. Percent change of GABA concentration is calculated from baseline (i.e., pre-rTMS). |
| Percent Change of Functional Connectivity in Left Motor Cortex, Where Functional Connectivity is Measured as a Dimensionless Fractional Amplitude of Low-frequency Fluctuations (fALFF), at 80 Min After rTMS | Baseline/Pre-rTMS and 80 min after rTMS | Functional connectivity is measured with MRI at 7 Tesla as a dimensionless fractional amplitude of low-frequency fluctuations (fALFF). This is an index which reflects the intensity of spontaneous regional brain activity. It is calculated as the ratio of power spectra of low frequency (0.01-0.08 Hz) to that of the entire frequency range. Percent change of functional connectivity is calculated from baseline (i.e., pre-rTMS). |
| Percent Change of Functional Connectivity in Right Motor Cortex, Where Functional Connectivity is Measured as a Dimensionless Fractional Amplitude of Low-frequency Fluctuations (fALFF), at 80 Min After rTMS | Baseline/Pre-rTMS and 80 min after rTMS | Functional connectivity is measured with MRI at 7 Tesla as a dimensionless fractional amplitude of low-frequency fluctuations (fALFF). This is an index which reflects the intensity of spontaneous regional brain activity. It is calculated as the ratio of power spectra of low frequency (0.01-0.08 Hz) to that of the entire frequency range. Percent change of functional connectivity is calculated from baseline (i.e., pre-rTMS). |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Inhibitory rTMS (1 Hz) Subjects are exposed to a 20-min inhibitory rTMS intervention that transiently suppresses the excitability of cortical structures beneath the site of stimulation. Subjects undergo MRI and MRS both before and right after the rTMS intervention. One week before the MRI/MRS acquisitions, neurophysiological parameters are also measured before and right after the rTMS intervention.
Inhibitory rTMS (1 Hz): Participants receive rTMS at a rate of 1 Hz, applied with a 70-mm figure-eight TMS coil connected to a stimulator, over the motor cortex hotspot contralateral to the dominant arm for 20 minutes at an intensity of 90% resting motor threshold (RMT) for a total of 600 TMS pulses. The total number of stimuli applied is well within the published safety guidelines for use of rTMS. rTMS is applied outside the scanner, whereas functional connectivity and neurochemistry are measured with MRI and MRS, respectively, at 7 Tesla. The MRI/MRS data are collected right before and immediately after the | 7 |
| Excitatory rTMS (5 Hz) Subjects are exposed to a 20-min excitatory rTMS intervention that transiently increases the net excitability of cortical structures beneath the site of stimulation. Subjects undergo MRI and MRS both before and right after the rTMS intervention. One week before the MRI/MRS acquisitions, neurophysiological parameters are also measured before and right after the rTMS intervention.
Excitatory rTMS (5 Hz): Participants receive rTMS at a rate of 5 Hz, applied with a 70-mm figure-eight TMS coil connected to a stimulator, over the motor cortex hotspot contralateral to the dominant arm for 20 minutes at an intensity of 90% RMT for a total of 600 TMS pulses. The total number of stimuli applied is well within the published safety guidelines for use of rTMS. rTMS is applied outside the scanner, whereas functional connectivity and neurochemistry are measured with MRI and MRS, respectively, at 7 Tesla. The MRI/MRS data are collected right before and immediately after the excitatory rTMS interv | 1 |
| Total | 8 |
Baseline characteristics
| Characteristic | Excitatory rTMS (5 Hz) | Total | Inhibitory rTMS (1 Hz) |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 1 Participants | 8 Participants | 7 Participants |
| Age, Continuous | 22 years | 27 years STANDARD_DEVIATION 7 | 28 years STANDARD_DEVIATION 7 |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) Black or African American | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 1 Participants | 7 Participants | 6 Participants |
| Region of Enrollment United States | 1 participants | 8 participants | 7 participants |
| Sex: Female, Male Female | 0 Participants | 0 Participants | 0 Participants |
| Sex: Female, Male Male | 1 Participants | 8 Participants | 7 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 7 | 0 / 1 |
| other Total, other adverse events | 7 / 7 | 1 / 1 |
| serious Total, serious adverse events | 0 / 7 | 0 / 1 |
Outcome results
Primary
Percent Change of Functional Connectivity in Left Motor Cortex, Where Functional Connectivity is Measured as a Dimensionless Fractional Amplitude of Low-frequency Fluctuations (fALFF), at 80 Min After rTMS
Functional connectivity is measured with MRI at 7 Tesla as a dimensionless fractional amplitude of low-frequency fluctuations (fALFF). This is an index which reflects the intensity of spontaneous regional brain activity. It is calculated as the ratio of power spectra of low frequency (0.01-0.08 Hz) to that of the entire frequency range. Percent change of functional connectivity is calculated from baseline (i.e., pre-rTMS).
Time frame: Baseline/Pre-rTMS and 80 min after rTMS
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Inhibitory rTMS (1 Hz) | Percent Change of Functional Connectivity in Left Motor Cortex, Where Functional Connectivity is Measured as a Dimensionless Fractional Amplitude of Low-frequency Fluctuations (fALFF), at 80 Min After rTMS | -2 percent change | Standard Deviation 11 |
| Excitatory rTMS (5 Hz) | Percent Change of Functional Connectivity in Left Motor Cortex, Where Functional Connectivity is Measured as a Dimensionless Fractional Amplitude of Low-frequency Fluctuations (fALFF), at 80 Min After rTMS | 9 percent change | — |
Primary
Percent Change of Functional Connectivity in Right Motor Cortex, Where Functional Connectivity is Measured as a Dimensionless Fractional Amplitude of Low-frequency Fluctuations (fALFF), at 80 Min After rTMS
Functional connectivity is measured with MRI at 7 Tesla as a dimensionless fractional amplitude of low-frequency fluctuations (fALFF). This is an index which reflects the intensity of spontaneous regional brain activity. It is calculated as the ratio of power spectra of low frequency (0.01-0.08 Hz) to that of the entire frequency range. Percent change of functional connectivity is calculated from baseline (i.e., pre-rTMS).
Time frame: Baseline/Pre-rTMS and 80 min after rTMS
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Inhibitory rTMS (1 Hz) | Percent Change of Functional Connectivity in Right Motor Cortex, Where Functional Connectivity is Measured as a Dimensionless Fractional Amplitude of Low-frequency Fluctuations (fALFF), at 80 Min After rTMS | -1 percent change | Standard Deviation 10 |
| Excitatory rTMS (5 Hz) | Percent Change of Functional Connectivity in Right Motor Cortex, Where Functional Connectivity is Measured as a Dimensionless Fractional Amplitude of Low-frequency Fluctuations (fALFF), at 80 Min After rTMS | 17 percent change | — |
Primary
Percent Change of GABA Concentration in a Voxel Encompassing the Left Motor Cortex, Measured at 30 Min After rTMS
GABA concentration is quantified with MRS at 7 Tesla. Percent change of GABA concentration is calculated from baseline (i.e., pre-rTMS).
Time frame: Baseline/Pre-rTMS and 30 min after rTMS
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Inhibitory rTMS (1 Hz) | Percent Change of GABA Concentration in a Voxel Encompassing the Left Motor Cortex, Measured at 30 Min After rTMS | 8 percent change | Standard Deviation 9 |
| Excitatory rTMS (5 Hz) | Percent Change of GABA Concentration in a Voxel Encompassing the Left Motor Cortex, Measured at 30 Min After rTMS | -27 percent change | — |
Primary
Percent Change of GABA Concentration in a Voxel Encompassing the Right Motor Cortex, Measured at 60 Min After rTMS
GABA concentration is quantified with MRS at 7 Tesla. Percent change of GABA concentration is calculated from baseline (i.e., pre-rTMS).
Time frame: Baseline/Pre-rTMS and 60 min after rTMS
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Inhibitory rTMS (1 Hz) | Percent Change of GABA Concentration in a Voxel Encompassing the Right Motor Cortex, Measured at 60 Min After rTMS | -6 percent change | Standard Deviation 6 |
| Excitatory rTMS (5 Hz) | Percent Change of GABA Concentration in a Voxel Encompassing the Right Motor Cortex, Measured at 60 Min After rTMS | 4 percent change | — |