Modeling TMS-induced Cortical Network Activity
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 入组人数
- 80
- 试验地点
- 1
- 主要终点
- Cortico-cortical evoked potential (ccEP) latencies
研究概览
简要总结
This is a study of normal brain physiology in healthy human volunteers. The study aims to understand the physiology of connectivity between brain regions. To reach this aim, it delivers single-pulse transcranial magnetic stimulation (spTMS) to one or two brain areas at a time while electroencephalography (EEG) is measured. When only one brain area is stimulated (uni-focal TMS), the goal is to record how many milliseconds it takes for the activity to spread from the stimulated area to other brain regions (conduction delay). When two brain areas are stimulated (bi-focal TMS), the TMS pulses are separated by a short millisecond-level time interval ("asynchrony") in a so-called paired associative stimulation (PAS) design. The central hypothesis is that PAS may increase or decrease connectivity between the stimulated areas depending on the asynchrony value. All techniques in the study are non-invasive and considered safe.
详细描述
The goal of the study is to illuminate the physiology of inter-regional connectivity in the human brain. Participants are healthy adult volunteers without disorders or medications influencing brain function (N=80). During uni-focal TMS, only one brain area is stimulated at a time, and the conduction delays and connectivity strengths between the stimulated brain area and other brain regions are quantified with source-resolved EEG. During the bi-focal TMS sessions, a range of negative and positive PAS asynchronies (from minus 50 to + 50 ms relative to the conduction delays) will be tested in separate sessions, and the within-session connectivity changes from PAS are estimated by applying uni-focal TMS before and after PAS. The targeted brain areas include the primary motor cortices in the left and right hemisphere as well as areas outside the primary motor cortices. All techniques included in the study are non-invasive and considered safe: TMS, EEG, electromyography (EMG), magnetic resonance imaging (MRI), diffusion MRI (dMRI), functional MRI (fMRI), and behavioral measures. The TMS parameters in this study are considered safe, as only single or pairs of TMS pulses are delivered.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 64 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Normal hearing and (corrected) vision
- •Able to understand and give informed consent
排除标准
- •Metal in the body (rods, plates, screws, shrapnel, dentures, IUD)
- •Metallic particles in the eye
- •Surgical clips in the head or previous neurosurgery
- •Cardiac pacemaker or pacemaker wires
- •Neurostimulators
- •Implanted pumps
- •Any magnetic particles in the body
- •Cochlear implants
- •Prosthetic heart valves
- •Epilepsy or any other type of seizure history
- •Significant claustrophobia
- •Meniere's disease
- •Pregnancy or breast-feeding
- •Diagnoses or medications (neurological or psychiatric) influencing brain function
- •History of, or current, substance abuse
- •History of developmental disorders (e.g., dyslexia)
- •Failure to perform the behavioral tasks
- •Prisoners
研究组 & 干预措施
Healthy participants
All participants participate in five core sessions. Session 1 consists of MRI scans (T1-weighted, T2-weighted, diffusion MRI, resting-state fMRI). Thereafter, there are four TMS-EEG sessions. Session 2 delivers uni-focal spTMS to various cortical targets while EEG is recorded to determine inter-regional conduction delays. Thereafter, Sessions 3 - 5 deliver bi-focal TMS (PAS), each session using a different asynchrony (shorter, equal to, or longer than the conduction delay). The three PAS sessions are at least one week apart. Each of the PAS sessions have three segments: (a) TMS-EEG-behavioral recordings before PAS, (b) the PAS modulation, and (c) TMS-EEG-behavioral recordings after PAS.
In addition to these core sessions, some participants may be invited for additional sessions for parameter optimization and for assessing test-retest repeatability.
干预措施: Sessions 3 - 5: Paired associative stimulation (PAS) (Device)
Healthy participants
All participants participate in five core sessions. Session 1 consists of MRI scans (T1-weighted, T2-weighted, diffusion MRI, resting-state fMRI). Thereafter, there are four TMS-EEG sessions. Session 2 delivers uni-focal spTMS to various cortical targets while EEG is recorded to determine inter-regional conduction delays. Thereafter, Sessions 3 - 5 deliver bi-focal TMS (PAS), each session using a different asynchrony (shorter, equal to, or longer than the conduction delay). The three PAS sessions are at least one week apart. Each of the PAS sessions have three segments: (a) TMS-EEG-behavioral recordings before PAS, (b) the PAS modulation, and (c) TMS-EEG-behavioral recordings after PAS.
In addition to these core sessions, some participants may be invited for additional sessions for parameter optimization and for assessing test-retest repeatability.
干预措施: Session 2: Single-pulse TMS (spTMS) (Device)
结局指标
主要结局
Cortico-cortical evoked potential (ccEP) latencies
时间窗: Recorded in the uni-focal TMS session, on average on Day 14 (Session 2). The ccEPs are measured once for each TMS location and intensity.
EEG/EMG are recorded with a 64/16-channel TMS-compatible device (NeurOne, Bittium, Kuopio, Finland) while spTMS is delivered. Thereafter, the sensor-space evoked potentials (EPs) undergo EEG source analysis to produce source-space ccEPs. For sessions with uni-focal TMS, the ccEPs latencies are used for determining the inter-regional conduction delays.
Change in cortico-cortical evoked potential (ccEP) amplitudes
时间窗: Recorded in each bi-focal TMS (PAS) session, on average on Days 28, 35, and 42 (Sessions 3, 4, and 5, respectively).
EEG/EMG are recorded with a 64/16-channel TMS-compatible device (NeurOne, Bittium, Kuopio, Finland) while spTMS is delivered. Thereafter, the sensor-space evoked potentials (EPs) undergo EEG source analysis to produce source-space ccEPs. For sessions with bi-focal TMS (PAS), the ccEPs amplitudes are used for determining the within-session effects of PAS by measuring the change in amplitudes before versus after the PAS modulation.
次要结局
- Change in bimanual coordination task (BCT) performance(Recorded in each bi-focal TMS (PAS) session, on average on Days 28, 35, and 42 (Sessions 3, 4, and 5, respectively).)
- MRI functional connectivity(Once on Day 1 (Session 1, before first TMS session).)
- Change in resting-state EEG (rs-EEG) connectivity using phase slope index (PSI)(Recorded in each bi-focal TMS (PAS) session, on average on Days 28, 35, and 42 (Sessions 3, 4, and 5, respectively).)
- MRI structural connectivity(Once on Day 1 (Session 1, before first TMS session).)
研究者
Aapo Nummenmaa
Assistant in Neuroscience
Massachusetts General Hospital