Transcranial Magnetic Stimulation (TMS): Uses and Configurations

A single TMS pulse can transiently perturb cortical activity and, over motor cortex, produce measurable motor-evoked potentials (MEPs)—electrical responses recorded from a muscle after stimulation of its motor-cortex representation. Paired-pulse TMS delivers two pulses separated by a controlled interval and is used to probe aspects of cortical excitability and inhibition. Repetitive TMS (rTMS) and patterned protocols such as theta-burst stimulation (TBS), a patterned protocol that delivers short high-frequency bursts in a repeated rhythm deliver trains of pulses and are used in research and in selected therapeutic applications.

The biological effect is not determined by frequency alone. Coil geometry, intensity, target, pulse pattern, number of sessions and individual anatomy all matter.

Evidence-based guidelines support rTMS for some neurological and psychiatric indications, but efficacy varies substantially by condition and protocol. Strong evidence for one target or disorder should not be generalized to another. [1,2]

TMS also requires formal safety screening, trained personnel and attention to seizure risk, hearing protection, implants and other contraindications or precautions. [1]

TMS can be used as a measurement, perturbation, mapping or therapeutic tool. The protocol determines which of these roles the system serves.

Neuronavigation is a guidance method that tracks the TMS coil relative to the participant’s head and an anatomical or functional brain image. This allows the operator to target a predefined cortical location and monitor coil position and orientation in real time. [3–5]

For research, neuronavigation improves reproducibility across sessions and participants. In clinical and surgical mapping, it can connect stimulation coordinates with individual anatomy rather than relying only on scalp landmarks.

Combining TMS with EEG allows researchers to stimulate a cortical region and record the resulting electrical response across the scalp. This can be powerful for studying effective connectivity, meaning the directed influence that activity in one brain region can exert on another, excitability and state-dependent responses. [3]

TMS–EEG is technically demanding because the pulse creates large electromagnetic, auditory and somatosensory artefacts. High-quality work therefore depends on specialized amplifiers, careful experimental control, preprocessing and, often, neuronavigation.

TMS platforms are configured around pulse protocol, coil geometry, targeting and accompanying measurements. Research setups often add neuronavigation, EMG or EEG.