Guidelines (TMS)🔗
Motor threshold🔗
For TMS, the intensity of pulses is set as a percentage of the individual motor threshold. The individual motor threshold varies greatly inter-subject, but also intra-subject between separate sessions. Thus, the individual motor threshold should always be re-estimated at the beginning of each session.
To prevent any risk for the participant, repetitive TMS is usually capped at 70 to 80% of the individual motor threshold and single pulse TMS is usually capped at 120% of the individual motor threshold.
Magstim devices🔗
The Magstim devices share common features: similar interface design, similar coil design, similar connector design.
The interface has 3 buttons, green, yellow, and red, used to control the stimulation pulses, and one nob used to set the stimulation settings.
The green button is used to charge the devices.
The yellow button is used to deliver a single pulse.
The red button is used to discharge the devices.
Attention
The Magstim devices should always be discharged before:
plugging/unplugging a coil
shutting down the device
Attention
When plugging or unplugging a coil, extreme care should be taken to avoid bending the pins.
When plugging the connector, position it as straight as possible, insert it gently in the correct orientation and tigheten the ring by turning it clockwise.
When unplugging the connector, untightened the ring by turning it counter-clockwise, support the connector cable with one hand to avoid any stress on the pins and pull the connector as straight as possible.
Pulse delviery can be controlled either by triggers, by pressing the yellow button on the interface or by pressing the connected pedal (if available). In anycase, the pulse will not be delivered if the button on the coil handle is not pressed simultaneously.
Tip
This safety features can be disabled by blocking the button on the handle of the coil in-place with a ziptie. Responsibilities for any damage or injury caused by this modification are on the user.
The pulse will not be delivered if the coil is overheating. In this case, please let the coil cool down before trying again.
Tip
Discharge the stimulator and replace the coil with a fresh one if needed.
Pulse delivery yields an audible click, which gets louder as the pulse intensity is increased.
Attention
If possible, avoid delivering pulses with the coil next to the stimulator or next to electronic devices, as it could damage them.
Piloting a TMS study🔗
For piloting purposes, an osciloscope can be used to measure the stimulation pulses via a 3-coil probe, measuring directly the magnetic field. The probe should be attached in the center of the TMS coil.