Transcranial magnetic stimulation (TMS) is a non-invasive method used to alter neuronal excitability across the scalp. Weak electric currents are generated in the outer layer of the brain using electromagnetic induction, allowing the study of specific cortical mechanisms (excitation/inhibition, neural plasticity) and brain connectivity in humans.
MBI houses the Magventure Magpro X100 with MagOption unit and several different coil types including non-cooled and cooled figure-of-eight designs. The Magventure system offers a wide range of functionality, enabling implementation of various experimental paradigms including:
- Single and paired pulse stimulation
- Repetitive stimulation
Additionally, there is a Brainsight TMS neuronavigation system that enables precise and individual navigation of a TMS coil above a specific anatomical area in the brain, as well as imaging-guided navigation of the TMS coil to functionally defined brain regions-of-interest.
We also have a range of sensors that connect to a PowerLab 26T data acquisition device, such as the BioAmp cable that can be used to record EMG signals.
In addition, the TMS laboratory houses a Compumedics Synamps2 EEG system with TMS-compatible EEG caps (EASYCAP) dedicated for concurrent TMS-EEG research.
TMS in MRI scanner
TMS is performed in the MRI 3T scanner by using a custom made 8-channel head coil. Use of an 8-channel head coil along with a stabilising frame provides room to manoeuvre the MRI-compatible TMS coil and fix it in position. This ensures accurate stimulation of target areas in the brain. TMS can also be timed to image acquisition during scans. This prevents TMS from corrupting scans whilst at the same time providing information on brain activation following stimulation.
Research using TMS at MBI
Monash University researchers, Professor Alex Fornito, Dr Nigel Rogasch and Dr Tribikram Thapa, are using MBI's TMS equipment and imaging facilities to investigate how the brain is connected, and how to best harness brain plasticity.
The team is using the unique capacity to deliver TMS within the MRI scanner to investigate how structures deep in the brain are activated by stimulating different cortical regions on the brain's surface.
In a separate project, they are applying a multi-modal approach to bridge the gap between molecular, cellular, and system-level explanations of TMS-induced plasticity in humans. They are using a combination of molecular genetics, electrophysiology, biophysical modelling, and experimental manipulation to uncover the physiological mechanisms of variability in TMS-induced plasticity across the cerebral cortex. Read more about this TMS research.