Brain Stimulation Lab
Researchers in the School use two kinds of brain stimulation in their experiments. The first is known as Transcranial Magnetic Stimulation (TMS), which involves passing a short-lasting magnetic field known as a pulse through the head of a participant. The pulse is generated using a specialised handheld device known as coil, and temporarily interrupts the functioning of those brain cells that are very near to centre of the coil. The TMS pulse does not cause any damage or injury. A good analogy of what happens is that ‘the phone is off the hook’—while the line is engaged by the TMS pulse, no other calls can be received.
TMS makes it possible for researchers to better understand whether particular brain areas are necessary in supporting particular behaviours, thought processes, and perceptual experiences. It is also possible to use TMS to temporarily change the functional ‘state’ of a brain area, making the brain area more or less responsive. This involves the application of repeated TMS pulses. The number of pulses and how they are timed determines whether the stimulated part of the brain will become more or less responsive. The change in brain state is temporary, and harmless. A useful analogy is to think about how a person’s ability to perform a task may depend on how well-rested they are, how confident they feel, etc.
The second kind of brain stimulation used in the School is known as transcranial direct current stimulation (tDCS). This involves the application of weak electrical currents applied to the surface of a participant’s head. Similar to repetitive TMS described above, tDCS is used to temporarily change the functional ‘state’ of a brain area, making the area more or less responsive. As such, researchers can use tDCS to learn whether and how changing the responsiveness of a particular part of the brain influences particular behaviours, thought processes, and perceptual experiences.
Both TMS and tDCS also have potential to help treat various clinical conditions and promote patient rehabilitation from illness or injury.
In the School we use two separate TMS systems supplied by Magstim to deliver single- and repetitive-pulse stimulation, which we combine with a Polaris neuronavigation system from Rogue Resolutions. Our tDCS equipment was also supplied by Rogue Resolutions. Both of these systems have been interfaced in experiments with equipment for eye-tracking, recording muscle activity (electromyography, EMG), recording brain activity using electroencephalography (EEG), and for recording body movements (kinematics).