LADYBIRD TMS-EEG

Passive electrodes contain no active electronic components at the scalp. This provides a direct Ag/AgCl recording interface and avoids placing a preamplifier close to the TMS stimulation field. The g.LADYbird Passive TMS-EEG is therefore particularly suited to TMS-EEG protocols where low electrode impedance, a simple signal path, and reliable measurement of early TMS-evoked potentials are priorities.

Artefact suppression is achieved through the complete TMS-EEG signal chain rather than the electrode alone. The g.LADYbird Passive TMS-EEG electrode contains no electronics, while the dedicated g.HIamp Passive Electrode Connector Box TMS incorporates additional filters specifically designed to suppress TMS artefacts. The connector box supports both single-pulse and repetitive TMS experiments.

The g.LADYbird passive TMS-EEG configuration is designed for rapid recovery of the recorded EEG signal following TMS stimulation, making it suitable for experiments investigating early TMS-evoked potentials. The exact recovery interval depends on the stimulation protocol, electrode preparation, cable configuration, stimulation site, and acquisition settings; therefore, recovery time should be evaluated under the specific experimental conditions rather than treated as a universal fixed value.

Low electrode impedance is particularly important for g.LADYbird Passive TMS-EEG. g.tec’s instructions recommend achieving the lowest possible impedance for all electrodes during TMS recordings. The passive g.LADYbird therefore requires careful skin preparation with abrasive gel to establish a low-impedance electrode-skin interface before recording.

Yes. Unlike the g.LADYbird Active TMS-EEG, the g.LADYbird Passive TMS-EEG electrode requires abrasive preparation to achieve the low electrode impedance appropriate for TMS-EEG. The preparation process creates a stable electrical interface between the sintered Ag/AgCl electrode and the skin. g.tec’s instructions for use specifically distinguish passive electrodes from active g.LADYbird electrodes, for which abrasive preparation is not required.

The main difference is the signal acquisition architecture. The g.LADYbird Passive TMS-EEG electrode has no integrated electronics and is intended for low-impedance recordings through the dedicated passive TMS signal path. The g.LADYbird active TMS-EEG electrode contains a miniature preamplifier directly in the electrode and can be used without abrasive skin preparation. Passive electrodes are therefore particularly relevant when a simple electrode architecture and low impedance are prioritized, whereas active electrodes provide a faster and less invasive preparation workflow.

The 3 mm profile minimizes the physical distance between the TMS coil and the scalp. This is particularly important when recording from electrodes located close to the stimulation site, where electrode geometry can constrain coil positioning. The g.LADYbird’s compact 18 mm electrode interface also limits the physical footprint around the stimulation area.

Cable routing is an important part of TMS-EEG artefact control. g.tec’s TMS-EEG setup keeps electrode wires as short as practical, routing them parallel to the head surface, preventing movement, avoiding loops, and bundling the cables together. The connector box should be positioned as far from the TMS stimulation site as practical. These measures reduce susceptibility to induced voltages and stimulation-related interference.

Yes. The dedicated g.HIamp Passive Electrode Connector Box TMS is designed for both single-pulse and repetitive TMS experiments. This makes the g.LADYbird Passive TMS-EEG electrodes suitable for protocols ranging from single-pulse TEP measurements to repetitive stimulation paradigms, provided that the complete experimental setup is configured appropriately for the stimulation protocol.

The g.GAMMAcap provides predefined electrode positions, allowing researchers to reproduce electrode montages across participants and recording sessions. It provides 74 labeled positions based on the extended 10/10 system plus 86 additional intermediate positions for flexible montages. The g.LADYbird Passive TMS-EEG can remain mounted in the cap during cleaning, which reduces repeated electrode insertion and helps maintain consistent configurations between experiments. Correct cap positioning using the Cz reference is recommended because predefined cap positions can deviate from anatomical 10–20 locations depending on head and cap geometry.